nats-server/server/norace_test.go

// Copyright 2018-2025 The NATS Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//go:build !race && !skip_no_race_tests
// +build !race,!skip_no_race_tests

package server

import (
	"bufio"
	"bytes"
	"compress/gzip"
	"context"
	"encoding/binary"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"math"
	"math/rand"
	"net"
	"net/http"
	"net/url"
	"os"
	"path/filepath"
	"reflect"
	"runtime"
	"runtime/debug"
	"slices"
	"strconv"
	"strings"
	"sync"
	"sync/atomic"
	"testing"
	"time"

	"crypto/hmac"
	crand "crypto/rand"
	"crypto/sha256"

	"github.com/klauspost/compress/s2"
	"github.com/nats-io/jwt/v2"
	"github.com/nats-io/nats-server/v2/server/avl"
	"github.com/nats-io/nats.go"
	"github.com/nats-io/nkeys"
	"github.com/nats-io/nuid"
)

// IMPORTANT: Tests in this file are not executed when running with the -race flag.
//            The test name should be prefixed with TestNoRace so we can run only
//            those tests: go test -run=TestNoRace ...

func TestNoRaceAvoidSlowConsumerBigMessages(t *testing.T) {
	opts := DefaultOptions() // Use defaults to make sure they avoid pending slow consumer.
	opts.NoSystemAccount = true
	s := RunServer(opts)
	defer s.Shutdown()

	nc1, err := nats.Connect(fmt.Sprintf("nats://%s:%d", opts.Host, opts.Port))
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	defer nc1.Close()

	nc2, err := nats.Connect(fmt.Sprintf("nats://%s:%d", opts.Host, opts.Port))
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	defer nc2.Close()

	data := make([]byte, 1024*1024) // 1MB payload
	crand.Read(data)

	expected := int32(500)
	received := int32(0)

	done := make(chan bool)

	// Create Subscription.
	nc1.Subscribe("slow.consumer", func(m *nats.Msg) {
		// Just eat it so that we are not measuring
		// code time, just delivery.
		atomic.AddInt32(&received, 1)
		if received >= expected {
			done <- true
		}
	})

	// Create Error handler
	nc1.SetErrorHandler(func(c *nats.Conn, s *nats.Subscription, err error) {
		t.Fatalf("Received an error on the subscription's connection: %v\n", err)
	})

	nc1.Flush()

	for i := 0; i < int(expected); i++ {
		nc2.Publish("slow.consumer", data)
	}
	nc2.Flush()

	select {
	case <-done:
		return
	case <-time.After(10 * time.Second):
		r := atomic.LoadInt32(&received)
		if s.NumSlowConsumers() > 0 {
			t.Fatalf("Did not receive all large messages due to slow consumer status: %d of %d", r, expected)
		}
		t.Fatalf("Failed to receive all large messages: %d of %d\n", r, expected)
	}
}

func TestNoRaceRoutedQueueAutoUnsubscribe(t *testing.T) {
	optsA, err := ProcessConfigFile("./configs/seed.conf")
	require_NoError(t, err)
	optsA.NoSigs, optsA.NoLog = true, true
	optsA.NoSystemAccount = true
	srvA := RunServer(optsA)
	defer srvA.Shutdown()

	srvARouteURL := fmt.Sprintf("nats://%s:%d", optsA.Cluster.Host, srvA.ClusterAddr().Port)
	optsB := nextServerOpts(optsA)
	optsB.Routes = RoutesFromStr(srvARouteURL)

	srvB := RunServer(optsB)
	defer srvB.Shutdown()

	// Wait for these 2 to connect to each other
	checkClusterFormed(t, srvA, srvB)

	// Have a client connection to each server
	ncA, err := nats.Connect(fmt.Sprintf("nats://%s:%d", optsA.Host, optsA.Port))
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	defer ncA.Close()

	ncB, err := nats.Connect(fmt.Sprintf("nats://%s:%d", optsB.Host, optsB.Port))
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	defer ncB.Close()

	rbar := int32(0)
	barCb := func(m *nats.Msg) {
		atomic.AddInt32(&rbar, 1)
	}
	rbaz := int32(0)
	bazCb := func(m *nats.Msg) {
		atomic.AddInt32(&rbaz, 1)
	}

	// Create 125 queue subs with auto-unsubscribe to each server for
	// group bar and group baz. So 250 total per queue group.
	cons := []*nats.Conn{ncA, ncB}
	for _, c := range cons {
		for i := 0; i < 100; i++ {
			qsub, err := c.QueueSubscribe("foo", "bar", barCb)
			if err != nil {
				t.Fatalf("Error on subscribe: %v", err)
			}
			if err := qsub.AutoUnsubscribe(1); err != nil {
				t.Fatalf("Error on auto-unsubscribe: %v", err)
			}
			qsub, err = c.QueueSubscribe("foo", "baz", bazCb)
			if err != nil {
				t.Fatalf("Error on subscribe: %v", err)
			}
			if err := qsub.AutoUnsubscribe(1); err != nil {
				t.Fatalf("Error on auto-unsubscribe: %v", err)
			}
		}
		c.Subscribe("TEST.COMPLETE", func(m *nats.Msg) {})
	}

	// We coelasce now so for each server we will have all local (200) plus
	// two from the remote side for each queue group. We also create one more
	// and will wait til each server has 204 subscriptions, that will make sure
	// that we have everything setup.
	checkFor(t, 10*time.Second, 100*time.Millisecond, func() error {
		subsA := srvA.NumSubscriptions()
		subsB := srvB.NumSubscriptions()
		if subsA != 204 || subsB != 204 {
			return fmt.Errorf("Not all subs processed yet: %d and %d", subsA, subsB)
		}
		return nil
	})

	expected := int32(200)
	// Now send messages from each server
	for i := int32(0); i < expected; i++ {
		c := cons[i%2]
		c.Publish("foo", []byte("Don't Drop Me!"))
	}
	for _, c := range cons {
		c.Flush()
	}

	checkFor(t, 10*time.Second, 100*time.Millisecond, func() error {
		nbar := atomic.LoadInt32(&rbar)
		nbaz := atomic.LoadInt32(&rbaz)
		if nbar == expected && nbaz == expected {
			return nil
		}
		return fmt.Errorf("Did not receive all %d queue messages, received %d for 'bar' and %d for 'baz'",
			expected, atomic.LoadInt32(&rbar), atomic.LoadInt32(&rbaz))
	})
}

func TestNoRaceClosedSlowConsumerWriteDeadline(t *testing.T) {
	opts := DefaultOptions()
	opts.NoSystemAccount = true
	opts.WriteDeadline = 10 * time.Millisecond // Make very small to trip.
	opts.MaxPending = 500 * 1024 * 1024        // Set high so it will not trip here.
	s := RunServer(opts)
	defer s.Shutdown()

	c, err := net.DialTimeout("tcp", fmt.Sprintf("%s:%d", opts.Host, opts.Port), 3*time.Second)
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	defer c.Close()
	if _, err := c.Write([]byte("CONNECT {}\r\nPING\r\nSUB foo 1\r\n")); err != nil {
		t.Fatalf("Error sending protocols to server: %v", err)
	}
	// Reduce socket buffer to increase reliability of data backing up in the server destined
	// for our subscribed client.
	c.(*net.TCPConn).SetReadBuffer(128)

	url := fmt.Sprintf("nats://%s:%d", opts.Host, opts.Port)
	sender, err := nats.Connect(url)
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	defer sender.Close()

	payload := make([]byte, 1024*1024)
	for i := 0; i < 100; i++ {
		if err := sender.Publish("foo", payload); err != nil {
			t.Fatalf("Error on publish: %v", err)
		}
	}

	// Flush sender connection to ensure that all data has been sent.
	if err := sender.Flush(); err != nil {
		t.Fatalf("Error on flush: %v", err)
	}

	// At this point server should have closed connection c.
	checkClosedConns(t, s, 1, 2*time.Second)
	conns := s.closedClients()
	if lc := len(conns); lc != 1 {
		t.Fatalf("len(conns) expected to be %d, got %d\n", 1, lc)
	}
	checkReason(t, conns[0].Reason, SlowConsumerWriteDeadline)
}

func TestNoRaceClosedSlowConsumerPendingBytes(t *testing.T) {
	opts := DefaultOptions()
	opts.NoSystemAccount = true
	opts.WriteDeadline = 30 * time.Second // Wait for long time so write deadline does not trigger slow consumer.
	opts.MaxPending = 1 * 1024 * 1024     // Set to low value (1MB) to allow SC to trip.
	s := RunServer(opts)
	defer s.Shutdown()

	c, err := net.DialTimeout("tcp", fmt.Sprintf("%s:%d", opts.Host, opts.Port), 3*time.Second)
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	defer c.Close()
	if _, err := c.Write([]byte("CONNECT {}\r\nPING\r\nSUB foo 1\r\n")); err != nil {
		t.Fatalf("Error sending protocols to server: %v", err)
	}
	// Reduce socket buffer to increase reliability of data backing up in the server destined
	// for our subscribed client.
	c.(*net.TCPConn).SetReadBuffer(128)

	url := fmt.Sprintf("nats://%s:%d", opts.Host, opts.Port)
	sender, err := nats.Connect(url)
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	defer sender.Close()

	payload := make([]byte, 1024*1024)
	for i := 0; i < 100; i++ {
		if err := sender.Publish("foo", payload); err != nil {
			t.Fatalf("Error on publish: %v", err)
		}
	}

	// Flush sender connection to ensure that all data has been sent.
	if err := sender.Flush(); err != nil {
		t.Fatalf("Error on flush: %v", err)
	}

	// At this point server should have closed connection c.
	checkClosedConns(t, s, 1, 2*time.Second)
	conns := s.closedClients()
	if lc := len(conns); lc != 1 {
		t.Fatalf("len(conns) expected to be %d, got %d\n", 1, lc)
	}
	checkReason(t, conns[0].Reason, SlowConsumerPendingBytes)
}

func TestNoRaceSlowConsumerPendingBytes(t *testing.T) {
	opts := DefaultOptions()
	opts.NoSystemAccount = true
	opts.WriteDeadline = 30 * time.Second // Wait for long time so write deadline does not trigger slow consumer.
	opts.MaxPending = 1 * 1024 * 1024     // Set to low value (1MB) to allow SC to trip.
	s := RunServer(opts)
	defer s.Shutdown()

	c, err := net.DialTimeout("tcp", fmt.Sprintf("%s:%d", opts.Host, opts.Port), 3*time.Second)
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	defer c.Close()
	if _, err := c.Write([]byte("CONNECT {}\r\nPING\r\nSUB foo 1\r\n")); err != nil {
		t.Fatalf("Error sending protocols to server: %v", err)
	}
	// Reduce socket buffer to increase reliability of data backing up in the server destined
	// for our subscribed client.
	c.(*net.TCPConn).SetReadBuffer(128)

	url := fmt.Sprintf("nats://%s:%d", opts.Host, opts.Port)
	sender, err := nats.Connect(url)
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	defer sender.Close()

	payload := make([]byte, 1024*1024)
	for i := 0; i < 100; i++ {
		if err := sender.Publish("foo", payload); err != nil {
			t.Fatalf("Error on publish: %v", err)
		}
	}

	// Flush sender connection to ensure that all data has been sent.
	if err := sender.Flush(); err != nil {
		t.Fatalf("Error on flush: %v", err)
	}

	// At this point server should have closed connection c.

	// On certain platforms, it may take more than one call before
	// getting the error.
	for i := 0; i < 100; i++ {
		if _, err := c.Write([]byte("PUB bar 5\r\nhello\r\n")); err != nil {
			// ok
			return
		}
	}
	t.Fatal("Connection should have been closed")
}

func TestNoRaceGatewayNoMissingReplies(t *testing.T) {
	// This test will have following setup:
	//
	// responder1		         requestor
	//    |                          |
	//    v                          v
	//   [A1]<-------gw------------[B1]
	//    |  \                      |
	//    |   \______gw__________   | route
	//    |                     _\| |
	//   [  ]--------gw----------->[  ]
	//   [A2]<-------gw------------[B2]
	//   [  ]                      [  ]
	//    ^
	//    |
	// responder2
	//
	// There is a possible race that when the requestor creates
	// a subscription on the reply subject, the subject interest
	// being sent from the inbound gateway, and B1 having none,
	// the SUB first goes to B2 before being sent to A1 from
	// B2's inbound GW. But the request can go from B1 to A1
	// right away and the responder1 connecting to A1 may send
	// back the reply before the interest on the reply makes it
	// to A1 (from B2).
	// This test will also verify that if the responder is instead
	// connected to A2, the reply is properly received by requestor
	// on B1.

	// For this test we want to be in interestOnly mode, so
	// make it happen quickly
	gatewayMaxRUnsubBeforeSwitch = 1
	defer func() { gatewayMaxRUnsubBeforeSwitch = defaultGatewayMaxRUnsubBeforeSwitch }()

	// Start with setting up A2 and B2.
	ob2 := testDefaultOptionsForGateway("B")
	sb2 := runGatewayServer(ob2)
	defer sb2.Shutdown()

	oa2 := testGatewayOptionsFromToWithServers(t, "A", "B", sb2)
	sa2 := runGatewayServer(oa2)
	defer sa2.Shutdown()

	waitForOutboundGateways(t, sa2, 1, time.Second)
	waitForInboundGateways(t, sa2, 1, time.Second)
	waitForOutboundGateways(t, sb2, 1, time.Second)
	waitForInboundGateways(t, sb2, 1, time.Second)

	// Now start A1 which will connect to B2
	oa1 := testGatewayOptionsFromToWithServers(t, "A", "B", sb2)
	oa1.Routes = RoutesFromStr(fmt.Sprintf("nats://%s:%d", oa2.Cluster.Host, oa2.Cluster.Port))
	sa1 := runGatewayServer(oa1)
	defer sa1.Shutdown()

	waitForOutboundGateways(t, sa1, 1, time.Second)
	waitForInboundGateways(t, sb2, 2, time.Second)

	checkClusterFormed(t, sa1, sa2)

	// Finally, start B1 that will connect to A1.
	ob1 := testGatewayOptionsFromToWithServers(t, "B", "A", sa1)
	ob1.Routes = RoutesFromStr(fmt.Sprintf("nats://%s:%d", ob2.Cluster.Host, ob2.Cluster.Port))
	sb1 := runGatewayServer(ob1)
	defer sb1.Shutdown()

	// Check that we have the outbound gateway from B1 to A1
	checkFor(t, 3*time.Second, 15*time.Millisecond, func() error {
		c := sb1.getOutboundGatewayConnection("A")
		if c == nil {
			return fmt.Errorf("Outbound connection to A not created yet")
		}
		c.mu.Lock()
		name := c.opts.Name
		nc := c.nc
		c.mu.Unlock()
		if name != sa1.ID() {
			// Force a disconnect
			nc.Close()
			return fmt.Errorf("Was unable to have B1 connect to A1")
		}
		return nil
	})

	waitForInboundGateways(t, sa1, 1, time.Second)
	checkClusterFormed(t, sb1, sb2)

	a1URL := fmt.Sprintf("nats://%s:%d", oa1.Host, oa1.Port)
	a2URL := fmt.Sprintf("nats://%s:%d", oa2.Host, oa2.Port)
	b1URL := fmt.Sprintf("nats://%s:%d", ob1.Host, ob1.Port)
	b2URL := fmt.Sprintf("nats://%s:%d", ob2.Host, ob2.Port)

	ncb1 := natsConnect(t, b1URL)
	defer ncb1.Close()

	ncb2 := natsConnect(t, b2URL)
	defer ncb2.Close()

	natsSubSync(t, ncb1, "just.a.sub")
	natsSubSync(t, ncb2, "just.a.sub")
	checkExpectedSubs(t, 2, sb1, sb2)

	// For this test, we want A to be checking B's interest in order
	// to send messages (which would cause replies to be dropped if
	// there is no interest registered on A). So from A servers,
	// send to various subjects and cause B's to switch to interestOnly
	// mode.
	nca1 := natsConnect(t, a1URL)
	defer nca1.Close()
	for i := 0; i < 10; i++ {
		natsPub(t, nca1, fmt.Sprintf("reject.%d", i), []byte("hello"))
	}
	nca2 := natsConnect(t, a2URL)
	defer nca2.Close()
	for i := 0; i < 10; i++ {
		natsPub(t, nca2, fmt.Sprintf("reject.%d", i), []byte("hello"))
	}

	checkSwitchedMode := func(t *testing.T, s *Server) {
		t.Helper()
		checkFor(t, 2*time.Second, 15*time.Millisecond, func() error {
			var switchedMode bool
			c := s.getOutboundGatewayConnection("B")
			ei, _ := c.gw.outsim.Load(globalAccountName)
			if ei != nil {
				e := ei.(*outsie)
				e.RLock()
				switchedMode = e.ni == nil && e.mode == InterestOnly
				e.RUnlock()
			}
			if !switchedMode {
				return fmt.Errorf("Still not switched mode")
			}
			return nil
		})
	}
	checkSwitchedMode(t, sa1)
	checkSwitchedMode(t, sa2)

	// Setup a subscriber on _INBOX.> on each of A's servers.
	total := 1000
	expected := int32(total)
	rcvOnA := int32(0)
	qrcvOnA := int32(0)
	natsSub(t, nca1, "myreply.>", func(_ *nats.Msg) {
		atomic.AddInt32(&rcvOnA, 1)
	})
	natsQueueSub(t, nca2, "myreply.>", "bar", func(_ *nats.Msg) {
		atomic.AddInt32(&qrcvOnA, 1)
	})
	checkExpectedSubs(t, 2, sa1, sa2)

	// Ok.. so now we will run the actual test where we
	// create a responder on A1 and make sure that every
	// single request from B1 gets the reply. Will repeat
	// test with responder connected to A2.
	sendReqs := func(t *testing.T, subConn *nats.Conn) {
		t.Helper()
		responder := natsSub(t, subConn, "foo", func(m *nats.Msg) {
			m.Respond([]byte("reply"))
		})
		natsFlush(t, subConn)
		checkExpectedSubs(t, 3, sa1, sa2)

		// We are not going to use Request() because this sets
		// a wildcard subscription on an INBOX and less likely
		// to produce the race. Instead we will explicitly set
		// the subscription on the reply subject and create one
		// per request.
		for i := 0; i < total/2; i++ {
			reply := fmt.Sprintf("myreply.%d", i)
			replySub := natsQueueSubSync(t, ncb1, reply, "bar")
			natsFlush(t, ncb1)

			// Let's make sure we have interest on B2.
			if r := sb2.globalAccount().sl.Match(reply); len(r.qsubs) == 0 {
				checkFor(t, time.Second, time.Millisecond, func() error {
					if r := sb2.globalAccount().sl.Match(reply); len(r.qsubs) == 0 {
						return fmt.Errorf("B still not registered interest on %s", reply)
					}
					return nil
				})
			}
			natsPubReq(t, ncb1, "foo", reply, []byte("request"))
			if _, err := replySub.NextMsg(time.Second); err != nil {
				t.Fatalf("Did not receive reply: %v", err)
			}
			natsUnsub(t, replySub)
		}

		responder.Unsubscribe()
		natsFlush(t, subConn)
		checkExpectedSubs(t, 2, sa1, sa2)
	}
	sendReqs(t, nca1)
	sendReqs(t, nca2)

	checkFor(t, time.Second, 15*time.Millisecond, func() error {
		if n := atomic.LoadInt32(&rcvOnA); n != expected {
			return fmt.Errorf("Subs on A expected to get %v replies, got %v", expected, n)
		}
		return nil
	})

	// We should not have received a single message on the queue sub
	// on cluster A because messages will have been delivered to
	// the member on cluster B.
	if n := atomic.LoadInt32(&qrcvOnA); n != 0 {
		t.Fatalf("Queue sub on A should not have received message, got %v", n)
	}
}

func TestNoRaceRouteMemUsage(t *testing.T) {
	oa := DefaultOptions()
	sa := RunServer(oa)
	defer sa.Shutdown()

	ob := DefaultOptions()
	ob.Routes = RoutesFromStr(fmt.Sprintf("nats://%s:%d", oa.Cluster.Host, oa.Cluster.Port))
	sb := RunServer(ob)
	defer sb.Shutdown()

	checkClusterFormed(t, sa, sb)

	responder := natsConnect(t, fmt.Sprintf("nats://%s:%d", oa.Host, oa.Port))
	defer responder.Close()
	for i := 0; i < 10; i++ {
		natsSub(t, responder, "foo", func(m *nats.Msg) {
			m.Respond(m.Data)
		})
	}
	natsFlush(t, responder)

	payload := make([]byte, 50*1024)

	bURL := fmt.Sprintf("nats://%s:%d", ob.Host, ob.Port)

	// Capture mem usage
	mem := runtime.MemStats{}
	runtime.ReadMemStats(&mem)
	inUseBefore := mem.HeapInuse

	for i := 0; i < 100; i++ {
		requestor := natsConnect(t, bURL)
		// Don't use a defer here otherwise that will make the memory check fail!
		// We are closing the connection just after these few instructions that
		// are not calling t.Fatal() anyway.
		inbox := nats.NewInbox()
		sub := natsSubSync(t, requestor, inbox)
		natsPubReq(t, requestor, "foo", inbox, payload)
		for j := 0; j < 10; j++ {
			natsNexMsg(t, sub, time.Second)
		}
		requestor.Close()
	}

	runtime.GC()
	debug.FreeOSMemory()
	runtime.ReadMemStats(&mem)
	inUseNow := mem.HeapInuse
	if inUseNow > 3*inUseBefore {
		t.Fatalf("Heap in-use before was %v, now %v: too high", inUseBefore, inUseNow)
	}
}

func TestNoRaceRouteCache(t *testing.T) {
	maxPerAccountCacheSize = 20
	prunePerAccountCacheSize = 5
	closedSubsCheckInterval = 250 * time.Millisecond

	defer func() {
		maxPerAccountCacheSize = defaultMaxPerAccountCacheSize
		prunePerAccountCacheSize = defaultPrunePerAccountCacheSize
		closedSubsCheckInterval = defaultClosedSubsCheckInterval
	}()

	for _, test := range []struct {
		name     string
		useQueue bool
	}{
		{"plain_sub", false},
		{"queue_sub", true},
	} {
		t.Run(test.name, func(t *testing.T) {

			oa := DefaultOptions()
			oa.NoSystemAccount = true
			oa.Cluster.PoolSize = -1
			sa := RunServer(oa)
			defer sa.Shutdown()

			ob := DefaultOptions()
			ob.NoSystemAccount = true
			ob.Cluster.PoolSize = -1
			ob.Routes = RoutesFromStr(fmt.Sprintf("nats://%s:%d", oa.Cluster.Host, oa.Cluster.Port))
			sb := RunServer(ob)
			defer sb.Shutdown()

			checkClusterFormed(t, sa, sb)

			responder := natsConnect(t, fmt.Sprintf("nats://%s:%d", oa.Host, oa.Port))
			defer responder.Close()
			natsSub(t, responder, "foo", func(m *nats.Msg) {
				m.Respond(m.Data)
			})
			natsFlush(t, responder)

			checkExpectedSubs(t, 1, sa)
			checkExpectedSubs(t, 1, sb)

			bURL := fmt.Sprintf("nats://%s:%d", ob.Host, ob.Port)
			requestor := natsConnect(t, bURL)
			defer requestor.Close()

			ch := make(chan struct{}, 1)
			cb := func(_ *nats.Msg) {
				select {
				case ch <- struct{}{}:
				default:
				}
			}

			sendReqs := func(t *testing.T, nc *nats.Conn, count int, unsub bool) {
				t.Helper()
				for i := 0; i < count; i++ {
					inbox := nats.NewInbox()
					var sub *nats.Subscription
					if test.useQueue {
						sub = natsQueueSub(t, nc, inbox, "queue", cb)
					} else {
						sub = natsSub(t, nc, inbox, cb)
					}
					natsPubReq(t, nc, "foo", inbox, []byte("hello"))
					select {
					case <-ch:
					case <-time.After(time.Second):
						t.Fatalf("Failed to get reply")
					}
					if unsub {
						natsUnsub(t, sub)
					}
				}
			}
			sendReqs(t, requestor, maxPerAccountCacheSize+1, true)

			var route *client
			sb.mu.Lock()
			route = getFirstRoute(sb)
			sb.mu.Unlock()

			checkExpected := func(t *testing.T, expected int) {
				t.Helper()
				checkFor(t, 2*time.Second, 15*time.Millisecond, func() error {
					route.mu.Lock()
					n := len(route.in.pacache)
					route.mu.Unlock()
					if n != expected {
						return fmt.Errorf("Expected %v subs in the cache, got %v", expected, n)
					}
					return nil
				})
			}
			checkExpected(t, (maxPerAccountCacheSize+1)-(prunePerAccountCacheSize+1))

			// Wait for more than the orphan check
			time.Sleep(2 * closedSubsCheckInterval)

			// Add a new subs up to point where new prune would occur
			sendReqs(t, requestor, prunePerAccountCacheSize+1, false)

			// Now closed subs should have been removed, so expected
			// subs in the cache should be the new ones.
			checkExpected(t, prunePerAccountCacheSize+1)

			// Now try wil implicit unsubscribe (due to connection close)
			sendReqs(t, requestor, maxPerAccountCacheSize+1, false)
			requestor.Close()

			checkExpected(t, maxPerAccountCacheSize-prunePerAccountCacheSize)

			// Wait for more than the orphan check
			time.Sleep(2 * closedSubsCheckInterval)

			// Now create new connection and send prunePerAccountCacheSize+1
			// and that should cause all subs from previous connection to be
			// removed from cache
			requestor = natsConnect(t, bURL)
			defer requestor.Close()

			sendReqs(t, requestor, prunePerAccountCacheSize+1, false)
			checkExpected(t, prunePerAccountCacheSize+1)
		})
	}
}

func TestNoRaceFetchAccountDoesNotRegisterAccountTwice(t *testing.T) {
	sa, oa, sb, ob, _ := runTrustedGateways(t)
	defer sa.Shutdown()
	defer sb.Shutdown()

	// Let's create a user account.
	okp, _ := nkeys.FromSeed(oSeed)
	akp, _ := nkeys.CreateAccount()
	pub, _ := akp.PublicKey()
	nac := jwt.NewAccountClaims(pub)
	jwt, _ := nac.Encode(okp)
	userAcc := pub

	// Replace B's account resolver with one that introduces
	// delay during the Fetch()
	sac := &slowAccResolver{AccountResolver: sb.AccountResolver()}
	sb.SetAccountResolver(sac)

	// Add the account in sa and sb
	addAccountToMemResolver(sa, userAcc, jwt)
	addAccountToMemResolver(sb, userAcc, jwt)

	// Tell the slow account resolver which account to slow down
	sac.Lock()
	sac.acc = userAcc
	sac.Unlock()

	urlA := fmt.Sprintf("nats://%s:%d", oa.Host, oa.Port)
	urlB := fmt.Sprintf("nats://%s:%d", ob.Host, ob.Port)

	nca, err := nats.Connect(urlA, createUserCreds(t, sa, akp))
	if err != nil {
		t.Fatalf("Error connecting to A: %v", err)
	}
	defer nca.Close()

	// Since there is an optimistic send, this message will go to B
	// and on processing this message, B will lookup/fetch this
	// account, which can produce race with the fetch of this
	// account from A's system account that sent a notification
	// about this account, or with the client connect just after
	// that.
	nca.Publish("foo", []byte("hello"))

	// Now connect and create a subscription on B
	ncb, err := nats.Connect(urlB, createUserCreds(t, sb, akp))
	if err != nil {
		t.Fatalf("Error connecting to A: %v", err)
	}
	defer ncb.Close()
	sub, err := ncb.SubscribeSync("foo")
	if err != nil {
		t.Fatalf("Error on subscribe: %v", err)
	}
	ncb.Flush()

	// Now send messages from A and B should ultimately start to receive
	// them (once the subscription has been correctly registered)
	ok := false
	for i := 0; i < 10; i++ {
		nca.Publish("foo", []byte("hello"))
		if _, err := sub.NextMsg(100 * time.Millisecond); err != nil {
			continue
		}
		ok = true
		break
	}
	if !ok {
		t.Fatalf("B should be able to receive messages")
	}

	checkTmpAccounts := func(t *testing.T, s *Server) {
		t.Helper()
		empty := true
		s.tmpAccounts.Range(func(_, _ any) bool {
			empty = false
			return false
		})
		if !empty {
			t.Fatalf("tmpAccounts is not empty")
		}
	}
	checkTmpAccounts(t, sa)
	checkTmpAccounts(t, sb)
}

func TestNoRaceWriteDeadline(t *testing.T) {
	opts := DefaultOptions()
	opts.NoSystemAccount = true
	opts.WriteDeadline = 30 * time.Millisecond
	s := RunServer(opts)
	defer s.Shutdown()

	c, err := net.DialTimeout("tcp", fmt.Sprintf("%s:%d", opts.Host, opts.Port), 3*time.Second)
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	defer c.Close()
	if _, err := c.Write([]byte("CONNECT {}\r\nPING\r\nSUB foo 1\r\n")); err != nil {
		t.Fatalf("Error sending protocols to server: %v", err)
	}
	// Reduce socket buffer to increase reliability of getting
	// write deadline errors.
	c.(*net.TCPConn).SetReadBuffer(4)

	url := fmt.Sprintf("nats://%s:%d", opts.Host, opts.Port)
	sender, err := nats.Connect(url)
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	defer sender.Close()

	payload := make([]byte, 1000000)
	total := 1000
	for i := 0; i < total; i++ {
		if err := sender.Publish("foo", payload); err != nil {
			t.Fatalf("Error on publish: %v", err)
		}
	}
	// Flush sender connection to ensure that all data has been sent.
	if err := sender.Flush(); err != nil {
		t.Fatalf("Error on flush: %v", err)
	}

	// At this point server should have closed connection c.

	// On certain platforms, it may take more than one call before
	// getting the error.
	for i := 0; i < 100; i++ {
		if _, err := c.Write([]byte("PUB bar 5\r\nhello\r\n")); err != nil {
			// ok
			return
		}
	}
	t.Fatal("Connection should have been closed")
}

func TestNoRaceLeafNodeClusterNameConflictDeadlock(t *testing.T) {
	o := DefaultOptions()
	o.LeafNode.Port = -1
	s := RunServer(o)
	defer s.Shutdown()

	u, err := url.Parse(fmt.Sprintf("nats://127.0.0.1:%d", o.LeafNode.Port))
	if err != nil {
		t.Fatalf("Error parsing url: %v", err)
	}

	o1 := DefaultOptions()
	o1.ServerName = "A1"
	o1.Cluster.Name = "clusterA"
	o1.LeafNode.Remotes = []*RemoteLeafOpts{{URLs: []*url.URL{u}}}
	s1 := RunServer(o1)
	defer s1.Shutdown()

	checkLeafNodeConnected(t, s1)

	o2 := DefaultOptions()
	o2.ServerName = "A2"
	o2.Cluster.Name = "clusterA"
	o2.Routes = RoutesFromStr(fmt.Sprintf("nats://127.0.0.1:%d", o1.Cluster.Port))
	o2.LeafNode.Remotes = []*RemoteLeafOpts{{URLs: []*url.URL{u}}}
	s2 := RunServer(o2)
	defer s2.Shutdown()

	checkLeafNodeConnected(t, s2)
	checkClusterFormed(t, s1, s2)

	o3 := DefaultOptions()
	o3.ServerName = "A3"
	o3.Cluster.Name = "" // intentionally not set
	o3.Routes = RoutesFromStr(fmt.Sprintf("nats://127.0.0.1:%d", o1.Cluster.Port))
	o3.LeafNode.Remotes = []*RemoteLeafOpts{{URLs: []*url.URL{u}}}
	s3 := RunServer(o3)
	defer s3.Shutdown()

	checkLeafNodeConnected(t, s3)
	checkClusterFormed(t, s1, s2, s3)
}

// This test is same than TestAccountAddServiceImportRace but running
// without the -race flag, it would capture more easily the possible
// duplicate sid, resulting in less than expected number of subscriptions
// in the account's internal subscriptions map.
func TestNoRaceAccountAddServiceImportRace(t *testing.T) {
	TestAccountAddServiceImportRace(t)
}

// Similar to the routed version. Make sure we receive all of the
// messages with auto-unsubscribe enabled.
func TestNoRaceQueueAutoUnsubscribe(t *testing.T) {
	opts := DefaultOptions()
	s := RunServer(opts)
	defer s.Shutdown()

	nc, err := nats.Connect(fmt.Sprintf("nats://%s:%d", opts.Host, opts.Port))
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	defer nc.Close()

	rbar := int32(0)
	barCb := func(m *nats.Msg) {
		atomic.AddInt32(&rbar, 1)
	}
	rbaz := int32(0)
	bazCb := func(m *nats.Msg) {
		atomic.AddInt32(&rbaz, 1)
	}

	// Create 1000 subscriptions with auto-unsubscribe of 1.
	// Do two groups, one bar and one baz.
	total := 1000
	for i := 0; i < total; i++ {
		qsub, err := nc.QueueSubscribe("foo", "bar", barCb)
		if err != nil {
			t.Fatalf("Error on subscribe: %v", err)
		}
		if err := qsub.AutoUnsubscribe(1); err != nil {
			t.Fatalf("Error on auto-unsubscribe: %v", err)
		}
		qsub, err = nc.QueueSubscribe("foo", "baz", bazCb)
		if err != nil {
			t.Fatalf("Error on subscribe: %v", err)
		}
		if err := qsub.AutoUnsubscribe(1); err != nil {
			t.Fatalf("Error on auto-unsubscribe: %v", err)
		}
	}
	nc.Flush()

	expected := int32(total)
	for i := int32(0); i < expected; i++ {
		nc.Publish("foo", []byte("Don't Drop Me!"))
	}
	nc.Flush()

	checkFor(t, 5*time.Second, 10*time.Millisecond, func() error {
		nbar := atomic.LoadInt32(&rbar)
		nbaz := atomic.LoadInt32(&rbaz)
		if nbar == expected && nbaz == expected {
			return nil
		}
		return fmt.Errorf("Did not receive all %d queue messages, received %d for 'bar' and %d for 'baz'",
			expected, atomic.LoadInt32(&rbar), atomic.LoadInt32(&rbaz))
	})
}

func TestNoRaceAcceptLoopsDoNotLeaveOpenedConn(t *testing.T) {
	for _, test := range []struct {
		name string
		url  func(o *Options) (string, int)
	}{
		{"client", func(o *Options) (string, int) { return o.Host, o.Port }},
		{"route", func(o *Options) (string, int) { return o.Cluster.Host, o.Cluster.Port }},
		{"gateway", func(o *Options) (string, int) { return o.Gateway.Host, o.Gateway.Port }},
		{"leafnode", func(o *Options) (string, int) { return o.LeafNode.Host, o.LeafNode.Port }},
		{"websocket", func(o *Options) (string, int) { return o.Websocket.Host, o.Websocket.Port }},
	} {
		t.Run(test.name, func(t *testing.T) {
			o := DefaultOptions()
			o.DisableShortFirstPing = true
			o.Accounts = []*Account{NewAccount("$SYS")}
			o.SystemAccount = "$SYS"
			o.Cluster.Name = "abc"
			o.Cluster.Host = "127.0.0.1"
			o.Cluster.Port = -1
			o.Gateway.Name = "abc"
			o.Gateway.Host = "127.0.0.1"
			o.Gateway.Port = -1
			o.LeafNode.Host = "127.0.0.1"
			o.LeafNode.Port = -1
			o.Websocket.Host = "127.0.0.1"
			o.Websocket.Port = -1
			o.Websocket.HandshakeTimeout = 1
			o.Websocket.NoTLS = true
			s := RunServer(o)
			defer s.Shutdown()

			host, port := test.url(o)
			url := fmt.Sprintf("%s:%d", host, port)
			var conns []net.Conn

			wg := sync.WaitGroup{}
			wg.Add(1)
			done := make(chan struct{}, 1)
			go func() {
				defer wg.Done()
				// Have an upper limit
				for i := 0; i < 200; i++ {
					c, err := net.Dial("tcp", url)
					if err != nil {
						return
					}
					conns = append(conns, c)
					select {
					case <-done:
						return
					default:
					}
				}
			}()
			time.Sleep(15 * time.Millisecond)
			s.Shutdown()
			close(done)
			wg.Wait()
			for _, c := range conns {
				c.SetReadDeadline(time.Now().Add(2 * time.Second))
				br := bufio.NewReader(c)
				// Read INFO for connections that were accepted
				_, _, err := br.ReadLine()
				if err == nil {
					// After that, the connection should be closed,
					// so we should get an error here.
					_, _, err = br.ReadLine()
				}
				// We expect an io.EOF or any other error indicating the use of a closed
				// connection, but we should not get the timeout error.
				if ne, ok := err.(net.Error); ok && ne.Timeout() {
					err = nil
				}
				if err == nil {
					var buf [10]byte
					c.SetDeadline(time.Now().Add(2 * time.Second))
					c.Write([]byte("C"))
					_, err = c.Read(buf[:])
					if ne, ok := err.(net.Error); ok && ne.Timeout() {
						err = nil
					}
				}
				if err == nil {
					t.Fatalf("Connection should have been closed")
				}
				c.Close()
			}
		})
	}
}

func TestNoRaceJetStreamDeleteStreamManyConsumers(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	mname := "MYS"
	mset, err := s.GlobalAccount().addStream(&StreamConfig{Name: mname, Storage: FileStorage})
	if err != nil {
		t.Fatalf("Unexpected error adding stream: %v", err)
	}

	// This number needs to be higher than the internal sendq size to trigger what this test is testing.
	for i := 0; i < 2000; i++ {
		_, err := mset.addConsumer(&ConsumerConfig{
			Durable:        fmt.Sprintf("D-%d", i),
			DeliverSubject: fmt.Sprintf("deliver.%d", i),
		})
		if err != nil {
			t.Fatalf("Error creating consumer: %v", err)
		}
	}
	// With bug this would not return and would hang.
	mset.delete()
}

// We used to swap accounts on an inbound message when processing service imports.
// Until JetStream this was kinda ok, but with JetStream we can have pull consumers
// trying to access the clients account in another Go routine now which causes issues.
// This is not limited to the case above, its just the one that exposed it.
// This test is to show that issue and that the fix works, meaning we no longer swap c.acc.
func TestNoRaceJetStreamServiceImportAccountSwapIssue(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	// Client based API
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo", "bar"},
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	sub, err := js.PullSubscribe("foo", "dlc")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	beforeSubs := s.NumSubscriptions()

	// How long we want both sides to run.
	timeout := time.Now().Add(3 * time.Second)
	errs := make(chan error, 1)

	// Publishing side, which will signal the consumer that is waiting and which will access c.acc. If publish
	// operation runs concurrently we will catch c.acc being $SYS some of the time.
	go func() {
		time.Sleep(100 * time.Millisecond)
		for time.Now().Before(timeout) {
			// This will signal the delivery of the pull messages.
			js.Publish("foo", []byte("Hello"))
			// This will swap the account because of JetStream service import.
			// We can get an error here with the bug or not.
			if _, err := js.StreamInfo("TEST"); err != nil {
				errs <- err
				return
			}
		}
		errs <- nil
	}()

	// Pull messages flow.
	var received int
	for time.Now().Before(timeout.Add(2 * time.Second)) {
		if msgs, err := sub.Fetch(1, nats.MaxWait(200*time.Millisecond)); err == nil {
			for _, m := range msgs {
				received++
				m.AckSync()
			}
		} else {
			break
		}
	}
	// Wait on publisher Go routine and check for errors.
	if err := <-errs; err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	// Double check all received.
	si, err := js.StreamInfo("TEST")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	if int(si.State.Msgs) != received {
		t.Fatalf("Expected to receive %d msgs, only got %d", si.State.Msgs, received)
	}
	// Now check for leaked subs from the fetch call above. That is what we first saw from the bug.
	if afterSubs := s.NumSubscriptions(); afterSubs != beforeSubs {
		t.Fatalf("Leaked subscriptions: %d before, %d after", beforeSubs, afterSubs)
	}
}

func TestNoRaceJetStreamAPIStreamListPaging(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	// Create 2X limit
	streamsNum := 2 * JSApiNamesLimit
	for i := 1; i <= streamsNum; i++ {
		name := fmt.Sprintf("STREAM-%06d", i)
		cfg := StreamConfig{Name: name, Storage: MemoryStorage}
		_, err := s.GlobalAccount().addStream(&cfg)
		if err != nil {
			t.Fatalf("Unexpected error adding stream: %v", err)
		}
	}

	// Client for API requests.
	nc := clientConnectToServer(t, s)
	defer nc.Close()

	reqList := func(offset int) []byte {
		t.Helper()
		var req []byte
		if offset > 0 {
			req, _ = json.Marshal(&ApiPagedRequest{Offset: offset})
		}
		resp, err := nc.Request(JSApiStreams, req, time.Second)
		if err != nil {
			t.Fatalf("Unexpected error getting stream list: %v", err)
		}
		return resp.Data
	}

	checkResp := func(resp []byte, expectedLen, expectedOffset int) {
		t.Helper()
		var listResponse JSApiStreamNamesResponse
		if err := json.Unmarshal(resp, &listResponse); err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		if len(listResponse.Streams) != expectedLen {
			t.Fatalf("Expected only %d streams but got %d", expectedLen, len(listResponse.Streams))
		}
		if listResponse.Total != streamsNum {
			t.Fatalf("Expected total to be %d but got %d", streamsNum, listResponse.Total)
		}
		if listResponse.Offset != expectedOffset {
			t.Fatalf("Expected offset to be %d but got %d", expectedOffset, listResponse.Offset)
		}
		if expectedLen < 1 {
			return
		}
		// Make sure we get the right stream.
		sname := fmt.Sprintf("STREAM-%06d", expectedOffset+1)
		if listResponse.Streams[0] != sname {
			t.Fatalf("Expected stream %q to be first, got %q", sname, listResponse.Streams[0])
		}
	}

	checkResp(reqList(0), JSApiNamesLimit, 0)
	checkResp(reqList(JSApiNamesLimit), JSApiNamesLimit, JSApiNamesLimit)
	checkResp(reqList(streamsNum), 0, streamsNum)
	checkResp(reqList(streamsNum-22), 22, streamsNum-22)
	checkResp(reqList(streamsNum+22), 0, streamsNum)
}

func TestNoRaceJetStreamAPIConsumerListPaging(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	sname := "MYSTREAM"
	mset, err := s.GlobalAccount().addStream(&StreamConfig{Name: sname})
	if err != nil {
		t.Fatalf("Unexpected error adding stream: %v", err)
	}

	// Client for API requests.
	nc := clientConnectToServer(t, s)
	defer nc.Close()

	consumersNum := JSApiNamesLimit
	for i := 1; i <= consumersNum; i++ {
		dsubj := fmt.Sprintf("d.%d", i)
		sub, _ := nc.SubscribeSync(dsubj)
		defer sub.Unsubscribe()
		nc.Flush()

		_, err := mset.addConsumer(&ConsumerConfig{DeliverSubject: dsubj})
		if err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
	}

	reqListSubject := fmt.Sprintf(JSApiConsumersT, sname)
	reqList := func(offset int) []byte {
		t.Helper()
		var req []byte
		if offset > 0 {
			req, _ = json.Marshal(&JSApiConsumersRequest{ApiPagedRequest: ApiPagedRequest{Offset: offset}})
		}
		resp, err := nc.Request(reqListSubject, req, time.Second)
		if err != nil {
			t.Fatalf("Unexpected error getting stream list: %v", err)
		}
		return resp.Data
	}

	checkResp := func(resp []byte, expectedLen, expectedOffset int) {
		t.Helper()
		var listResponse JSApiConsumerNamesResponse
		if err := json.Unmarshal(resp, &listResponse); err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		if len(listResponse.Consumers) != expectedLen {
			t.Fatalf("Expected only %d streams but got %d", expectedLen, len(listResponse.Consumers))
		}
		if listResponse.Total != consumersNum {
			t.Fatalf("Expected total to be %d but got %d", consumersNum, listResponse.Total)
		}
		if listResponse.Offset != expectedOffset {
			t.Fatalf("Expected offset to be %d but got %d", expectedOffset, listResponse.Offset)
		}
	}

	checkResp(reqList(0), JSApiNamesLimit, 0)
	checkResp(reqList(consumersNum-22), 22, consumersNum-22)
	checkResp(reqList(consumersNum+22), 0, consumersNum)
}

func TestNoRaceJetStreamWorkQueueLoadBalance(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	mname := "MY_MSG_SET"
	mset, err := s.GlobalAccount().addStream(&StreamConfig{Name: mname, Subjects: []string{"foo", "bar"}})
	if err != nil {
		t.Fatalf("Unexpected error adding message set: %v", err)
	}
	defer mset.delete()

	// Create basic work queue mode consumer.
	oname := "WQ"
	o, err := mset.addConsumer(&ConsumerConfig{Durable: oname, AckPolicy: AckExplicit})
	if err != nil {
		t.Fatalf("Expected no error with durable, got %v", err)
	}
	defer o.delete()

	// To send messages.
	nc := clientConnectToServer(t, s)
	defer nc.Close()

	// For normal work queue semantics, you send requests to the subject with stream and consumer name.
	reqMsgSubj := o.requestNextMsgSubject()

	numWorkers := 25
	counts := make([]int32, numWorkers)
	var received int32

	rwg := &sync.WaitGroup{}
	rwg.Add(numWorkers)

	wg := &sync.WaitGroup{}
	wg.Add(numWorkers)
	ch := make(chan bool)

	toSend := 1000

	for i := 0; i < numWorkers; i++ {
		nc := clientConnectToServer(t, s)
		defer nc.Close()

		go func(index int32) {
			rwg.Done()
			defer wg.Done()
			<-ch

			for counter := &counts[index]; ; {
				m, err := nc.Request(reqMsgSubj, nil, 100*time.Millisecond)
				if err != nil {
					return
				}
				m.Respond(nil)
				atomic.AddInt32(counter, 1)
				if total := atomic.AddInt32(&received, 1); total >= int32(toSend) {
					return
				}
			}
		}(int32(i))
	}

	// Wait for requestors to be ready
	rwg.Wait()
	close(ch)

	sendSubj := "bar"
	for i := 0; i < toSend; i++ {
		sendStreamMsg(t, nc, sendSubj, "Hello World!")
	}

	// Wait for test to complete.
	wg.Wait()

	target := toSend / numWorkers
	delta := target/2 + 5
	low, high := int32(target-delta), int32(target+delta)

	for i := 0; i < numWorkers; i++ {
		if msgs := atomic.LoadInt32(&counts[i]); msgs < low || msgs > high {
			t.Fatalf("Messages received for worker [%d] too far off from target of %d, got %d", i, target, msgs)
		}
	}
}

func TestNoRaceJetStreamClusterLargeStreamInlineCatchup(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "LSS", 3)
	defer c.shutdown()

	// Client based API
	s := c.randomServer()
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo"},
		Replicas: 3,
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	sr := c.randomNonStreamLeader("$G", "TEST")
	sr.Shutdown()

	// In case sr was meta leader.
	c.waitOnLeader()

	msg, toSend := []byte("Hello JS Clustering"), 5000

	// Now fill up stream.
	for i := 0; i < toSend; i++ {
		if _, err = js.Publish("foo", msg); err != nil {
			t.Fatalf("Unexpected publish error: %v", err)
		}
	}
	si, err := js.StreamInfo("TEST")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	// Check active state as well, shows that the owner answered.
	if si.State.Msgs != uint64(toSend) {
		t.Fatalf("Expected %d msgs, got bad state: %+v", toSend, si.State)
	}

	// Kill our current leader to make just 2.
	c.streamLeader("$G", "TEST").Shutdown()

	// Now restart the shutdown peer and wait for it to be current.
	sr = c.restartServer(sr)
	c.waitOnStreamCurrent(sr, "$G", "TEST")

	// Ask other servers to stepdown as leader so that sr becomes the leader.
	checkFor(t, 20*time.Second, 200*time.Millisecond, func() error {
		c.waitOnStreamLeader("$G", "TEST")
		if sl := c.streamLeader("$G", "TEST"); sl != sr {
			sl.JetStreamStepdownStream("$G", "TEST")
			return fmt.Errorf("Server %s is not leader yet", sr)
		}
		return nil
	})

	si, err = js.StreamInfo("TEST")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	// Check that we have all of our messsages stored.
	// Wait for a bit for upper layers to process.
	checkFor(t, 2*time.Second, 100*time.Millisecond, func() error {
		if si.State.Msgs != uint64(toSend) {
			return fmt.Errorf("Expected %d msgs, got %d", toSend, si.State.Msgs)
		}
		return nil
	})
}

func TestNoRaceJetStreamClusterStreamCreateAndLostQuorum(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R5S", 3)
	defer c.shutdown()

	// Client based API
	s := c.randomServer()
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	sub, err := nc.SubscribeSync(JSAdvisoryStreamQuorumLostPre + ".*")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	if _, err := js.AddStream(&nats.StreamConfig{Name: "NO-LQ-START", Replicas: 3}); err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	c.waitOnStreamLeader("$G", "NO-LQ-START")
	checkSubsPending(t, sub, 0)

	c.stopAll()
	// Start up the one we were connected to first and wait for it to be connected.
	s = c.restartServer(s)
	nc, err = nats.Connect(s.ClientURL())
	if err != nil {
		t.Fatalf("Failed to create client: %v", err)
	}
	defer nc.Close()

	sub, err = nc.SubscribeSync(JSAdvisoryStreamQuorumLostPre + ".*")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	nc.Flush()

	c.restartAll()
	c.waitOnStreamLeader("$G", "NO-LQ-START")

	checkSubsPending(t, sub, 0)
}

func TestNoRaceJetStreamSuperClusterMirrors(t *testing.T) {
	sc := createJetStreamSuperCluster(t, 3, 3)
	defer sc.shutdown()

	// Client based API
	s := sc.clusterForName("C2").randomServer()
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	// Create source stream.
	_, err := js.AddStream(&nats.StreamConfig{Name: "S1", Subjects: []string{"foo", "bar"}, Replicas: 3, Placement: &nats.Placement{Cluster: "C2"}})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	// Needed while Go client does not have mirror support.
	createStream := func(cfg *nats.StreamConfig) {
		t.Helper()
		if _, err := js.AddStream(cfg); err != nil {
			t.Fatalf("Unexpected error: %+v", err)
		}
	}

	// Send 100 messages.
	for i := 0; i < 100; i++ {
		if _, err := js.Publish("foo", []byte("MIRRORS!")); err != nil {
			t.Fatalf("Unexpected publish error: %v", err)
		}
	}

	createStream(&nats.StreamConfig{
		Name:      "M1",
		Mirror:    &nats.StreamSource{Name: "S1"},
		Placement: &nats.Placement{Cluster: "C1"},
	})

	checkFor(t, 2*time.Second, 100*time.Millisecond, func() error {
		si, err := js.StreamInfo("M1")
		if err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		if si.State.Msgs != 100 {
			return fmt.Errorf("Expected 100 msgs, got state: %+v", si.State)
		}
		return nil
	})

	// Purge the source stream.
	if err := js.PurgeStream("S1"); err != nil {
		t.Fatalf("Unexpected purge error: %v", err)
	}
	// Send 50 more msgs now.
	for i := 0; i < 50; i++ {
		if _, err := js.Publish("bar", []byte("OK")); err != nil {
			t.Fatalf("Unexpected publish error: %v", err)
		}
	}

	createStream(&nats.StreamConfig{
		Name:      "M2",
		Mirror:    &nats.StreamSource{Name: "S1"},
		Replicas:  3,
		Placement: &nats.Placement{Cluster: "C3"},
	})

	checkFor(t, 10*time.Second, 100*time.Millisecond, func() error {
		si, err := js.StreamInfo("M2")
		if err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		if si.State.Msgs != 50 {
			return fmt.Errorf("Expected 50 msgs, got state: %+v", si.State)
		}
		if si.State.FirstSeq != 101 {
			return fmt.Errorf("Expected start seq of 101, got state: %+v", si.State)
		}
		return nil
	})

	sl := sc.clusterForName("C3").streamLeader("$G", "M2")
	doneCh := make(chan bool)

	// Now test that if the mirror get's interrupted that it picks up where it left off etc.
	go func() {
		// Send 100 more messages.
		for i := 0; i < 100; i++ {
			if _, err := js.Publish("foo", []byte("MIRRORS!")); err != nil {
				t.Errorf("Unexpected publish on %d error: %v", i, err)
			}
			time.Sleep(2 * time.Millisecond)
		}
		doneCh <- true
	}()

	time.Sleep(20 * time.Millisecond)
	sl.Shutdown()

	<-doneCh
	sc.clusterForName("C3").waitOnStreamLeader("$G", "M2")

	checkFor(t, 10*time.Second, 100*time.Millisecond, func() error {
		si, err := js.StreamInfo("M2")
		if err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		if si.State.Msgs != 150 {
			return fmt.Errorf("Expected 150 msgs, got state: %+v", si.State)
		}
		if si.State.FirstSeq != 101 {
			return fmt.Errorf("Expected start seq of 101, got state: %+v", si.State)
		}
		return nil
	})
}

func TestNoRaceJetStreamSuperClusterMixedModeMirrors(t *testing.T) {
	// Unlike the similar sources test, this test is not reliably catching the bug
	// that would cause mirrors to not have the expected messages count.
	// Still, adding this test in case we have a regression and we are lucky in
	// getting the failure while running this.

	tmpl := `
		listen: 127.0.0.1:-1
		server_name: %s
		jetstream: { domain: ngs, max_mem_store: 256MB, max_file_store: 2GB, store_dir: '%s'}
		leaf: { listen: 127.0.0.1:-1 }

		cluster {
			name: %s
			listen: 127.0.0.1:%d
			routes = [%s]
		}

		accounts { $SYS { users = [ { user: "admin", pass: "s3cr3t!" } ] } }
	`
	sc := createJetStreamSuperClusterWithTemplateAndModHook(t, tmpl, 7, 4,
		func(serverName, clusterName, storeDir, conf string) string {
			sname := serverName[strings.Index(serverName, "-")+1:]
			switch sname {
			case "S5", "S6", "S7":
				conf = strings.ReplaceAll(conf, "jetstream: { ", "#jetstream: { ")
			default:
				conf = strings.ReplaceAll(conf, "leaf: { ", "#leaf: { ")
			}
			return conf
		}, nil)
	defer sc.shutdown()

	// Connect our client to a non JS server
	c := sc.randomCluster()
	var s *Server
	for {
		if as := c.randomServer(); !as.JetStreamEnabled() {
			s = as
			break
		}
	}
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	numStreams := 10
	toSend := 1000
	errCh := make(chan error, numStreams)
	wg := sync.WaitGroup{}
	wg.Add(numStreams)
	// Create 10 origin streams
	for i := 0; i < 10; i++ {
		go func(idx int) {
			defer wg.Done()
			name := fmt.Sprintf("S%d", idx+1)
			if _, err := js.AddStream(&nats.StreamConfig{Name: name}); err != nil {
				errCh <- fmt.Errorf("unexpected error: %v", err)
				return
			}
			c.waitOnStreamLeader(globalAccountName, name)
			// Load them up with a bunch of messages.
			for n := 0; n < toSend; n++ {
				m := nats.NewMsg(name)
				m.Header.Set("stream", name)
				m.Header.Set("idx", strconv.FormatInt(int64(n+1), 10))
				if err := nc.PublishMsg(m); err != nil {
					errCh <- fmt.Errorf("unexpected publish error: %v", err)
				}
			}
		}(i)
	}
	wg.Wait()
	select {
	case err := <-errCh:
		t.Fatal(err)
	default:
	}

	for i := 0; i < 3; i++ {
		// Now create our mirrors
		wg := sync.WaitGroup{}
		mirrorsCount := 10
		wg.Add(mirrorsCount)
		errCh := make(chan error, 1)
		for m := 0; m < mirrorsCount; m++ {
			sname := fmt.Sprintf("S%d", rand.Intn(10)+1)
			go func(sname string, mirrorIdx int) {
				defer wg.Done()
				if _, err := js.AddStream(&nats.StreamConfig{
					Name:     fmt.Sprintf("M%d", mirrorIdx),
					Mirror:   &nats.StreamSource{Name: sname},
					Replicas: 3,
				}); err != nil {
					select {
					case errCh <- err:
					default:
					}
				}
			}(sname, m+1)
		}
		wg.Wait()
		select {
		case err := <-errCh:
			t.Fatalf("Error creating mirrors: %v", err)
		default:
		}
		// Now check the mirrors have all expected messages
		for m := 0; m < mirrorsCount; m++ {
			name := fmt.Sprintf("M%d", m+1)
			checkFor(t, 15*time.Second, 500*time.Millisecond, func() error {
				si, err := js.StreamInfo(name)
				if err != nil {
					t.Fatalf("Could not retrieve stream info")
				}
				if si.State.Msgs != uint64(toSend) {
					return fmt.Errorf("Expected %d msgs, got state: %+v", toSend, si.State)
				}
				return nil
			})
			err := js.DeleteStream(name)
			require_NoError(t, err)
		}
	}
}

func TestNoRaceJetStreamSuperClusterSources(t *testing.T) {
	owt := srcConsumerWaitTime
	srcConsumerWaitTime = 2 * time.Second
	defer func() { srcConsumerWaitTime = owt }()

	sc := createJetStreamSuperCluster(t, 3, 3)
	defer sc.shutdown()

	// Client based API
	s := sc.clusterForName("C1").randomServer()
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	// Create our source streams.
	for _, sname := range []string{"foo", "bar", "baz"} {
		if _, err := js.AddStream(&nats.StreamConfig{Name: sname, Replicas: 1}); err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
	}

	sendBatch := func(subject string, n int) {
		for i := 0; i < n; i++ {
			msg := fmt.Sprintf("MSG-%d", i+1)
			if _, err := js.Publish(subject, []byte(msg)); err != nil {
				t.Fatalf("Unexpected publish error: %v", err)
			}
		}
	}
	// Populate each one.
	sendBatch("foo", 10)
	sendBatch("bar", 15)
	sendBatch("baz", 25)

	// Needed while Go client does not have mirror support for creating mirror or source streams.
	createStream := func(cfg *nats.StreamConfig) {
		t.Helper()
		if _, err := js.AddStream(cfg); err != nil {
			t.Fatalf("Unexpected error: %+v", err)
		}
	}

	cfg := &nats.StreamConfig{
		Name: "MS",
		Sources: []*nats.StreamSource{
			{Name: "foo"},
			{Name: "bar"},
			{Name: "baz"},
		},
	}

	createStream(cfg)
	time.Sleep(time.Second)

	// Faster timeout since we loop below checking for condition.
	js2, err := nc.JetStream(nats.MaxWait(50 * time.Millisecond))
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	checkFor(t, 10*time.Second, 100*time.Millisecond, func() error {
		si, err := js2.StreamInfo("MS")
		if err != nil {
			return err
		}
		if si.State.Msgs != 50 {
			return fmt.Errorf("Expected 50 msgs, got state: %+v", si.State)
		}
		return nil
	})

	// Purge the source streams.
	for _, sname := range []string{"foo", "bar", "baz"} {
		if err := js.PurgeStream(sname); err != nil {
			t.Fatalf("Unexpected purge error: %v", err)
		}
	}

	if err := js.DeleteStream("MS"); err != nil {
		t.Fatalf("Unexpected delete error: %v", err)
	}

	// Send more msgs now.
	sendBatch("foo", 10)
	sendBatch("bar", 15)
	sendBatch("baz", 25)

	cfg = &nats.StreamConfig{
		Name: "MS2",
		Sources: []*nats.StreamSource{
			{Name: "foo"},
			{Name: "bar"},
			{Name: "baz"},
		},
		Replicas:  3,
		Placement: &nats.Placement{Cluster: "C3"},
	}

	createStream(cfg)

	checkFor(t, 5*time.Second, 100*time.Millisecond, func() error {
		si, err := js2.StreamInfo("MS2")
		if err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		if si.State.Msgs != 50 {
			return fmt.Errorf("Expected 50 msgs, got state: %+v", si.State)
		}
		if si.State.FirstSeq != 1 {
			return fmt.Errorf("Expected start seq of 1, got state: %+v", si.State)
		}
		return nil
	})

	sl := sc.clusterForName("C3").streamLeader("$G", "MS2")
	doneCh := make(chan bool)

	if sl == sc.leader() {
		snc, _ := jsClientConnect(t, sc.randomServer(), nats.UserInfo("admin", "s3cr3t!"))
		defer snc.Close()
		_, err := snc.Request(JSApiLeaderStepDown, nil, time.Second)
		require_NoError(t, err)
		sc.waitOnLeader()
	}

	// Now test that if the mirror get's interrupted that it picks up where it left off etc.
	go func() {
		// Send 50 more messages each.
		for i := 0; i < 50; i++ {
			msg := fmt.Sprintf("R-MSG-%d", i+1)
			for _, sname := range []string{"foo", "bar", "baz"} {
				m := nats.NewMsg(sname)
				m.Data = []byte(msg)
				if _, err := js.PublishMsg(m); err != nil {
					t.Errorf("Unexpected publish error: %v", err)
				}
			}
			time.Sleep(2 * time.Millisecond)
		}
		doneCh <- true
	}()

	time.Sleep(20 * time.Millisecond)
	sl.Shutdown()

	sc.clusterForName("C3").waitOnStreamLeader("$G", "MS2")
	<-doneCh

	checkFor(t, 20*time.Second, time.Second, func() error {
		si, err := js2.StreamInfo("MS2")
		if err != nil {
			return err
		}
		if si.State.Msgs != 200 {
			return fmt.Errorf("Expected 200 msgs, got state: %+v", si.State)
		}
		return nil
	})
}

func TestNoRaceJetStreamClusterSourcesMuxd(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "SMUX", 3)
	defer c.shutdown()

	// Client for API requests.
	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	// Send in 10000 messages.
	msg, toSend := make([]byte, 1024), 10000
	crand.Read(msg)

	var sources []*nats.StreamSource
	// Create 10 origin streams.
	for i := 1; i <= 10; i++ {
		name := fmt.Sprintf("O-%d", i)
		if _, err := js.AddStream(&nats.StreamConfig{Name: name}); err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		// Make sure we have a leader before publishing, especially since we use
		// non JS publisher, we would not know if the messages made it to those
		// streams or not.
		c.waitOnStreamLeader(globalAccountName, name)
		// Load them up with a bunch of messages.
		for n := 0; n < toSend; n++ {
			if err := nc.Publish(name, msg); err != nil {
				t.Fatalf("Unexpected publish error: %v", err)
			}
		}
		sources = append(sources, &nats.StreamSource{Name: name})
	}

	// Now create our downstream stream that sources from all of them.
	if _, err := js.AddStream(&nats.StreamConfig{Name: "S", Replicas: 2, Sources: sources}); err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	checkFor(t, 20*time.Second, 500*time.Millisecond, func() error {
		si, err := js.StreamInfo("S")
		if err != nil {
			t.Fatalf("Could not retrieve stream info")
		}
		if si.State.Msgs != uint64(10*toSend) {
			return fmt.Errorf("Expected %d msgs, got state: %+v", toSend*10, si.State)
		}
		return nil
	})

}

func TestNoRaceJetStreamSuperClusterMixedModeSources(t *testing.T) {
	tmpl := `
		listen: 127.0.0.1:-1
		server_name: %s
		jetstream: { domain: ngs, max_mem_store: 256MB, max_file_store: 2GB, store_dir: '%s'}
		leaf: { listen: 127.0.0.1:-1 }

		cluster {
			name: %s
			listen: 127.0.0.1:%d
			routes = [%s]
		}

		accounts { $SYS { users = [ { user: "admin", pass: "s3cr3t!" } ] } }
	`
	sc := createJetStreamSuperClusterWithTemplateAndModHook(t, tmpl, 7, 2,
		func(serverName, clusterName, storeDir, conf string) string {
			sname := serverName[strings.Index(serverName, "-")+1:]
			switch sname {
			case "S5", "S6", "S7":
				conf = strings.ReplaceAll(conf, "jetstream: { ", "#jetstream: { ")
			default:
				conf = strings.ReplaceAll(conf, "leaf: { ", "#leaf: { ")
			}
			return conf
		}, nil)
	defer sc.shutdown()
	// Connect our client to a non JS server
	c := sc.randomCluster()
	var s *Server
	for {
		if as := c.randomServer(); !as.JetStreamEnabled() {
			s = as
			break
		}
	}
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	numStreams := 100
	toSend := 1000
	var sources []*nats.StreamSource
	errCh := make(chan error, numStreams)
	srcCh := make(chan *nats.StreamSource, numStreams)
	wg := sync.WaitGroup{}
	wg.Add(numStreams)
	// Create 100 origin streams.
	for i := 1; i <= numStreams; i++ {
		go func(idx int) {
			defer wg.Done()

			name := fmt.Sprintf("O-%d", idx)
			if _, err := js.AddStream(&nats.StreamConfig{Name: name}); err != nil {
				errCh <- fmt.Errorf("unexpected error: %v", err)
				return
			}
			c.waitOnStreamLeader(globalAccountName, name)
			// Load them up with a bunch of messages.
			for n := 0; n < toSend; n++ {
				m := nats.NewMsg(name)
				m.Header.Set("stream", name)
				m.Header.Set("idx", strconv.FormatInt(int64(n+1), 10))
				if err := nc.PublishMsg(m); err != nil {
					errCh <- fmt.Errorf("unexpected publish error: %v", err)
					return
				}
			}
			srcCh <- &nats.StreamSource{Name: name}
		}(i)
	}
	wg.Wait()
	select {
	case err := <-errCh:
		t.Fatal(err)
	default:
	}
	for i := 0; i < numStreams; i++ {
		sources = append(sources, <-srcCh)
	}

	for i := 0; i < 3; i++ {
		// Now create our downstream stream that sources from all of them.
		if _, err := js.AddStream(&nats.StreamConfig{Name: "S", Replicas: 3, Sources: sources}); err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}

		checkFor(t, 15*time.Second, 1000*time.Millisecond, func() error {
			si, err := js.StreamInfo("S")
			if err != nil {
				t.Fatalf("Could not retrieve stream info")
			}
			if si.State.Msgs != uint64(numStreams*toSend) {
				return fmt.Errorf("Expected %d msgs, got state: %+v", numStreams*toSend, si.State)
			}
			return nil
		})

		err := js.DeleteStream("S")
		require_NoError(t, err)
	}
}

func TestNoRaceJetStreamClusterExtendedStreamPurgeStall(t *testing.T) {
	// Uncomment to run. Needs to be on a big machine. Do not want as part of Travis tests atm.
	skip(t)

	cerr := func(t *testing.T, err error) {
		t.Helper()
		if err != nil {
			t.Fatalf("unexepected err: %s", err)
		}
	}

	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	si, err := js.AddStream(&nats.StreamConfig{
		Name:     "KV",
		Subjects: []string{"kv.>"},
		Storage:  nats.FileStorage,
	})
	cerr(t, err)

	// 100kb messages spread over 1000 different subjects
	body := make([]byte, 100*1024)
	for i := 0; i < 50000; i++ {
		if _, err := js.PublishAsync(fmt.Sprintf("kv.%d", i%1000), body); err != nil {
			cerr(t, err)
		}
	}
	checkFor(t, 5*time.Second, 200*time.Millisecond, func() error {
		if si, err = js.StreamInfo("KV"); err != nil {
			return err
		}
		if si.State.Msgs == 50000 {
			return nil
		}
		return fmt.Errorf("waiting for more")
	})

	jp, _ := json.Marshal(&JSApiStreamPurgeRequest{Subject: "kv.20"})
	start := time.Now()
	res, err := nc.Request(fmt.Sprintf(JSApiStreamPurgeT, "KV"), jp, time.Minute)
	elapsed := time.Since(start)
	cerr(t, err)
	pres := JSApiStreamPurgeResponse{}
	err = json.Unmarshal(res.Data, &pres)
	cerr(t, err)
	if !pres.Success {
		t.Fatalf("purge failed: %#v", pres)
	}
	if elapsed > time.Second {
		t.Fatalf("Purge took too long %s", elapsed)
	}
	v, _ := s.Varz(nil)
	if v.Mem > 100*1024*1024 { // 100MB limit but in practice < 100MB -> Was ~7GB when failing.
		t.Fatalf("Used too much memory: %v", friendlyBytes(v.Mem))
	}
}

func TestNoRaceJetStreamClusterMirrorExpirationAndMissingSequences(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "MMS", 9)
	defer c.shutdown()

	// Client for API requests.
	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	sendBatch := func(n int) {
		t.Helper()
		// Send a batch to a given subject.
		for i := 0; i < n; i++ {
			if _, err := js.Publish("TEST", []byte("OK")); err != nil {
				t.Fatalf("Unexpected publish error: %v", err)
			}
		}
	}

	checkStream := func(stream string, num uint64) {
		t.Helper()
		checkFor(t, 20*time.Second, 20*time.Millisecond, func() error {
			si, err := js.StreamInfo(stream)
			if err != nil {
				return err
			}
			if si.State.Msgs != num {
				return fmt.Errorf("Expected %d msgs, got %d", num, si.State.Msgs)
			}
			return nil
		})
	}

	checkMirror := func(num uint64) { t.Helper(); checkStream("M", num) }
	checkTest := func(num uint64) { t.Helper(); checkStream("TEST", num) }

	// Origin
	_, err := js.AddStream(&nats.StreamConfig{
		Name:   "TEST",
		MaxAge: 500 * time.Millisecond,
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	ts := c.streamLeader("$G", "TEST")
	ml := c.leader()

	// Create mirror now.
	for ms := ts; ms == ts || ms == ml; {
		_, err = js.AddStream(&nats.StreamConfig{
			Name:     "M",
			Mirror:   &nats.StreamSource{Name: "TEST"},
			Replicas: 2,
		})
		if err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		ms = c.streamLeader("$G", "M")
		if ts == ms || ms == ml {
			// Delete and retry.
			js.DeleteStream("M")
		}
	}

	sendBatch(10)
	checkMirror(10)

	// Now shutdown the server with the mirror.
	ms := c.streamLeader("$G", "M")
	ms.Shutdown()
	c.waitOnLeader()

	// Send more messages but let them expire.
	sendBatch(10)
	checkTest(0)

	c.restartServer(ms)
	c.checkClusterFormed()
	c.waitOnStreamLeader("$G", "M")

	sendBatch(10)
	checkMirror(20)
}

func TestNoRaceJetStreamClusterLargeActiveOnReplica(t *testing.T) {
	// Uncomment to run.
	skip(t)

	c := createJetStreamClusterExplicit(t, "LAG", 3)
	defer c.shutdown()

	// Client for API requests.
	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	timeout := time.Now().Add(60 * time.Second)
	for time.Now().Before(timeout) {
		si, err := js.AddStream(&nats.StreamConfig{
			Name:     "TEST",
			Subjects: []string{"foo", "bar"},
			Replicas: 3,
		})
		if err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		for _, r := range si.Cluster.Replicas {
			if r.Active > 5*time.Second {
				t.Fatalf("Bad Active value: %+v", r)
			}
		}
		if err := js.DeleteStream("TEST"); err != nil {
			t.Fatalf("Unexpected delete error: %v", err)
		}
	}
}

func TestNoRaceJetStreamSuperClusterRIPStress(t *testing.T) {
	// Uncomment to run. Needs to be on a big machine.
	skip(t)

	sc := createJetStreamSuperCluster(t, 3, 3)
	defer sc.shutdown()

	// Client based API
	s := sc.clusterForName("C2").randomServer()
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	scm := make(map[string][]string)

	// Create 50 streams per cluster.
	for _, cn := range []string{"C1", "C2", "C3"} {
		var streams []string
		for i := 0; i < 50; i++ {
			sn := fmt.Sprintf("%s-S%d", cn, i+1)
			streams = append(streams, sn)
			_, err := js.AddStream(&nats.StreamConfig{
				Name:      sn,
				Replicas:  3,
				Placement: &nats.Placement{Cluster: cn},
				MaxAge:    2 * time.Minute,
				MaxMsgs:   50_000,
			})
			if err != nil {
				t.Fatalf("Unexpected error: %v", err)
			}
		}
		scm[cn] = streams
	}

	sourceForCluster := func(cn string) []*nats.StreamSource {
		var sns []string
		switch cn {
		case "C1":
			sns = scm["C2"]
		case "C2":
			sns = scm["C3"]
		case "C3":
			sns = scm["C1"]
		default:
			t.Fatalf("Unknown cluster %q", cn)
		}
		var ss []*nats.StreamSource
		for _, sn := range sns {
			ss = append(ss, &nats.StreamSource{Name: sn})
		}
		return ss
	}

	// Mux all 50 streams from one cluster to a single stream across a GW connection to another cluster.
	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "C1-S-MUX",
		Replicas:  2,
		Placement: &nats.Placement{Cluster: "C1"},
		Sources:   sourceForCluster("C2"),
		MaxAge:    time.Minute,
		MaxMsgs:   20_000,
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	_, err = js.AddStream(&nats.StreamConfig{
		Name:      "C2-S-MUX",
		Replicas:  2,
		Placement: &nats.Placement{Cluster: "C2"},
		Sources:   sourceForCluster("C3"),
		MaxAge:    time.Minute,
		MaxMsgs:   20_000,
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	_, err = js.AddStream(&nats.StreamConfig{
		Name:      "C3-S-MUX",
		Replicas:  2,
		Placement: &nats.Placement{Cluster: "C3"},
		Sources:   sourceForCluster("C1"),
		MaxAge:    time.Minute,
		MaxMsgs:   20_000,
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	// Now create mirrors for our mux'd streams.
	_, err = js.AddStream(&nats.StreamConfig{
		Name:      "C1-MIRROR",
		Replicas:  3,
		Placement: &nats.Placement{Cluster: "C1"},
		Mirror:    &nats.StreamSource{Name: "C3-S-MUX"},
		MaxAge:    5 * time.Minute,
		MaxMsgs:   10_000,
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	_, err = js.AddStream(&nats.StreamConfig{
		Name:      "C2-MIRROR",
		Replicas:  3,
		Placement: &nats.Placement{Cluster: "C2"},
		Mirror:    &nats.StreamSource{Name: "C2-S-MUX"},
		MaxAge:    5 * time.Minute,
		MaxMsgs:   10_000,
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	_, err = js.AddStream(&nats.StreamConfig{
		Name:      "C3-MIRROR",
		Replicas:  3,
		Placement: &nats.Placement{Cluster: "C3"},
		Mirror:    &nats.StreamSource{Name: "C1-S-MUX"},
		MaxAge:    5 * time.Minute,
		MaxMsgs:   10_000,
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	var jsc []nats.JetStream

	// Create 64 clients.
	for i := 0; i < 64; i++ {
		s := sc.randomCluster().randomServer()
		nc, _ := jsClientConnect(t, s)
		defer nc.Close()
		js, err := nc.JetStream(nats.PublishAsyncMaxPending(8 * 1024))
		if err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		jsc = append(jsc, js)
	}

	msg := make([]byte, 1024)
	crand.Read(msg)

	// 10 minutes
	expires := time.Now().Add(480 * time.Second)
	for time.Now().Before(expires) {
		for _, sns := range scm {
			rand.Shuffle(len(sns), func(i, j int) { sns[i], sns[j] = sns[j], sns[i] })
			for _, sn := range sns {
				js := jsc[rand.Intn(len(jsc))]
				if _, err = js.PublishAsync(sn, msg); err != nil {
					t.Fatalf("Unexpected publish error: %v", err)
				}
			}
		}
		time.Sleep(10 * time.Millisecond)
	}
}

func TestNoRaceJetStreamSlowFilteredInititalPendingAndFirstMsg(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	// Create directly here to force multiple blocks, etc.
	a, err := s.LookupAccount("$G")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	mset, err := a.addStreamWithStore(
		&StreamConfig{
			Name:     "S",
			Subjects: []string{"foo", "bar", "baz", "foo.bar.baz", "foo.*"},
		},
		&FileStoreConfig{
			BlockSize:  4 * 1024 * 1024,
			AsyncFlush: true,
		},
	)
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	toSend := 100_000 // 500k total though.

	// Messages will be 'foo' 'bar' 'baz' repeated 100k times.
	// Then 'foo.bar.baz' all contigous for 100k.
	// Then foo.N for 1-100000
	for i := 0; i < toSend; i++ {
		js.PublishAsync("foo", []byte("HELLO"))
		js.PublishAsync("bar", []byte("WORLD"))
		js.PublishAsync("baz", []byte("AGAIN"))
	}
	// Make contiguous block of same subject.
	for i := 0; i < toSend; i++ {
		js.PublishAsync("foo.bar.baz", []byte("ALL-TOGETHER"))
	}
	// Now add some more at the end.
	for i := 0; i < toSend; i++ {
		js.PublishAsync(fmt.Sprintf("foo.%d", i+1), []byte("LATER"))
	}

	checkFor(t, 10*time.Second, 250*time.Millisecond, func() error {
		si, err := js.StreamInfo("S")
		if err != nil {
			return err
		}
		if si.State.Msgs != uint64(5*toSend) {
			return fmt.Errorf("Expected %d msgs, got %d", 5*toSend, si.State.Msgs)
		}
		return nil
	})

	// Threshold for taking too long.
	const thresh = 150 * time.Millisecond

	var dindex int
	testConsumerCreate := func(subj string, startSeq, expectedNumPending uint64) {
		t.Helper()
		dindex++
		dname := fmt.Sprintf("dur-%d", dindex)
		cfg := ConsumerConfig{FilterSubject: subj, Durable: dname, AckPolicy: AckExplicit}
		if startSeq > 1 {
			cfg.OptStartSeq, cfg.DeliverPolicy = startSeq, DeliverByStartSequence
		}
		start := time.Now()
		o, err := mset.addConsumer(&cfg)
		if err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		if delta := time.Since(start); delta > thresh {
			t.Fatalf("Creating consumer for %q and start: %d took too long: %v", subj, startSeq, delta)
		}
		if ci := o.info(); ci.NumPending != expectedNumPending {
			t.Fatalf("Expected NumPending of %d, got %d", expectedNumPending, ci.NumPending)
		}
	}

	testConsumerCreate("foo.100000", 1, 1)
	testConsumerCreate("foo.100000", 222_000, 1)
	testConsumerCreate("foo", 1, 100_000)
	testConsumerCreate("foo", 4, 100_000-1)
	testConsumerCreate("foo.bar.baz", 1, 100_000)
	testConsumerCreate("foo.bar.baz", 350_001, 50_000)
	testConsumerCreate("*", 1, 300_000)
	testConsumerCreate("*", 4, 300_000-3)
	testConsumerCreate(">", 1, 500_000)
	testConsumerCreate(">", 50_000, 500_000-50_000+1)
	testConsumerCreate("foo.10", 1, 1)

	// Also test that we do not take long if the start sequence is later in the stream.
	sub, err := js.PullSubscribe("foo.100000", "dlc")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	start := time.Now()
	fetchMsgs(t, sub, 1, time.Second)
	if delta := time.Since(start); delta > thresh {
		t.Fatalf("Took too long for pull subscriber to fetch the message: %v", delta)
	}

	// Now do some deletes and make sure these are handled correctly.
	// Delete 3 foo messages.
	mset.removeMsg(1)
	mset.removeMsg(4)
	mset.removeMsg(7)
	testConsumerCreate("foo", 1, 100_000-3)

	// Make sure wider scoped subjects do the right thing from a pending perspective.
	o, err := mset.addConsumer(&ConsumerConfig{FilterSubject: ">", Durable: "cat", AckPolicy: AckExplicit})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	ci, expected := o.info(), uint64(500_000-3)
	if ci.NumPending != expected {
		t.Fatalf("Expected NumPending of %d, got %d", expected, ci.NumPending)
	}
	// Send another and make sure its captured by our wide scope consumer.
	js.Publish("foo", []byte("HELLO AGAIN"))
	if ci = o.info(); ci.NumPending != expected+1 {
		t.Fatalf("Expected the consumer to recognize the wide scoped consumer, wanted pending of %d, got %d", expected+1, ci.NumPending)
	}

	// Stop current server and test restart..
	sd := s.JetStreamConfig().StoreDir
	s.Shutdown()
	// Restart.
	s = RunJetStreamServerOnPort(-1, sd)
	defer s.Shutdown()

	a, err = s.LookupAccount("$G")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	mset, err = a.lookupStream("S")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	// Make sure we recovered our per subject state on restart.
	testConsumerCreate("foo.100000", 1, 1)
	testConsumerCreate("foo", 1, 100_000-2)
}

func TestNoRaceJetStreamFileStoreBufferReuse(t *testing.T) {
	// Uncomment to run. Needs to be on a big machine.
	skip(t)

	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	cfg := &StreamConfig{Name: "TEST", Subjects: []string{"foo", "bar", "baz"}, Storage: FileStorage}
	if _, err := s.GlobalAccount().addStreamWithStore(cfg, nil); err != nil {
		t.Fatalf("Unexpected error adding stream: %v", err)
	}

	// Client for API requests.
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	toSend := 200_000

	m := nats.NewMsg("foo")
	m.Data = make([]byte, 8*1024)
	crand.Read(m.Data)

	start := time.Now()
	for i := 0; i < toSend; i++ {
		m.Reply = _EMPTY_
		switch i % 3 {
		case 0:
			m.Subject = "foo"
		case 1:
			m.Subject = "bar"
		case 2:
			m.Subject = "baz"
		}
		m.Header.Set("X-ID2", fmt.Sprintf("XXXXX-%d", i))
		if _, err := js.PublishMsgAsync(m); err != nil {
			t.Fatalf("Err on publish: %v", err)
		}
	}
	<-js.PublishAsyncComplete()
	fmt.Printf("TOOK %v to publish\n", time.Since(start))

	v, err := s.Varz(nil)
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	fmt.Printf("MEM AFTER PUBLISH is %v\n", friendlyBytes(v.Mem))

	si, _ := js.StreamInfo("TEST")
	fmt.Printf("si is %+v\n", si.State)

	received := 0
	done := make(chan bool)

	cb := func(m *nats.Msg) {
		received++
		if received >= toSend {
			done <- true
		}
	}

	start = time.Now()
	sub, err := js.Subscribe("*", cb, nats.EnableFlowControl(), nats.IdleHeartbeat(time.Second), nats.AckNone())
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	defer sub.Unsubscribe()
	<-done
	fmt.Printf("TOOK %v to consume\n", time.Since(start))

	v, err = s.Varz(nil)
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	fmt.Printf("MEM AFTER SUBSCRIBE is %v\n", friendlyBytes(v.Mem))
}

// Report of slow restart for a server that has many messages that have expired while it was not running.
func TestNoRaceJetStreamSlowRestartWithManyExpiredMsgs(t *testing.T) {
	opts := DefaultTestOptions
	opts.Port = -1
	opts.JetStream = true
	s := RunServer(&opts)
	if config := s.JetStreamConfig(); config != nil {
		defer removeDir(t, config.StoreDir)
	}
	defer s.Shutdown()

	// Client for API requests.
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	ttl := 2 * time.Second
	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "ORDERS",
		Subjects: []string{"orders.*"},
		MaxAge:   ttl,
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	// Attach a consumer who is filtering on a wildcard subject as well.
	// This does not affect it like I thought originally but will keep it here.
	_, err = js.AddConsumer("ORDERS", &nats.ConsumerConfig{
		Durable:       "c22",
		FilterSubject: "orders.*",
		AckPolicy:     nats.AckExplicitPolicy,
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	// Now fill up with messages.
	toSend := 100_000
	for i := 1; i <= toSend; i++ {
		js.PublishAsync(fmt.Sprintf("orders.%d", i), []byte("OK"))
	}
	<-js.PublishAsyncComplete()

	sdir := strings.TrimSuffix(s.JetStreamConfig().StoreDir, JetStreamStoreDir)
	s.Shutdown()

	// Let them expire while not running.
	time.Sleep(ttl + 500*time.Millisecond)

	start := time.Now()
	opts.Port = -1
	opts.StoreDir = sdir
	s = RunServer(&opts)
	elapsed := time.Since(start)
	defer s.Shutdown()

	if elapsed > 2*time.Second {
		t.Fatalf("Took %v for restart which is too long", elapsed)
	}

	// Check everything is correct.
	nc, js = jsClientConnect(t, s)
	defer nc.Close()

	si, err := js.StreamInfo("ORDERS")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	if si.State.Msgs != 0 {
		t.Fatalf("Expected no msgs after restart, got %d", si.State.Msgs)
	}
}

func TestNoRaceJetStreamStalledMirrorsAfterExpire(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "JSC", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	cfg := &nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo.*"},
		Replicas: 1,
		MaxAge:   100 * time.Millisecond,
	}

	if _, err := js.AddStream(cfg); err != nil {
		t.Fatalf("Error creating stream: %v", err)
	}

	if _, err := js.AddStream(&nats.StreamConfig{
		Name:     "M",
		Replicas: 2,
		Mirror:   &nats.StreamSource{Name: "TEST"},
	}); err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	sendBatch := func(batch int) {
		t.Helper()
		for i := 0; i < batch; i++ {
			js.PublishAsync("foo.bar", []byte("Hello"))
		}
		select {
		case <-js.PublishAsyncComplete():
		case <-time.After(5 * time.Second):
			t.Fatalf("Did not receive completion signal")
		}
	}

	numMsgs := 10_000
	sendBatch(numMsgs)

	// Turn off expiration so we can test we did not stall.
	cfg.MaxAge = 0
	if _, err := js.UpdateStream(cfg); err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	sendBatch(numMsgs)

	// Wait for mirror to be caught up.
	checkFor(t, 10*time.Second, 500*time.Millisecond, func() error {
		si, err := js.StreamInfo("M")
		if err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		if si.State.LastSeq != uint64(2*numMsgs) {
			return fmt.Errorf("Expected %d as last sequence, got state: %+v", 2*numMsgs, si.State)
		}
		return nil
	})
}

// We will use JetStream helpers to create supercluster but this test is about exposing the ability to access
// account scoped connz with subject interest filtering.
func TestNoRaceJetStreamSuperClusterAccountConnz(t *testing.T) {
	// This has 4 different account, 3 general and system.
	sc := createJetStreamSuperClusterWithTemplate(t, jsClusterAccountsTempl, 3, 3)
	defer sc.shutdown()

	// Create 20 connections on account one and two
	// Create JetStream assets for each as well to make sure by default we do not report them.
	num := 20
	for i := 0; i < num; i++ {
		nc, _ := jsClientConnect(t, sc.randomServer(), nats.UserInfo("one", "p"), nats.Name("one"))
		defer nc.Close()

		if i%2 == 0 {
			nc.SubscribeSync("foo")
		} else {
			nc.SubscribeSync("bar")
		}

		nc, js := jsClientConnect(t, sc.randomServer(), nats.UserInfo("two", "p"), nats.Name("two"))
		defer nc.Close()
		nc.SubscribeSync("baz")
		nc.SubscribeSync("foo.bar.*")
		nc.SubscribeSync(fmt.Sprintf("id.%d", i+1))

		js.AddStream(&nats.StreamConfig{Name: fmt.Sprintf("TEST:%d", i+1)})
	}

	type czapi struct {
		Server *ServerInfo
		Data   *Connz
		Error  *ApiError
	}

	parseConnz := func(buf []byte) *Connz {
		t.Helper()
		var cz czapi
		if err := json.Unmarshal(buf, &cz); err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		if cz.Error != nil {
			t.Fatalf("Unexpected error: %+v", cz.Error)
		}
		return cz.Data
	}

	doRequest := func(reqSubj, acc, filter string, expected int) {
		t.Helper()
		nc, _ := jsClientConnect(t, sc.randomServer(), nats.UserInfo(acc, "p"), nats.Name(acc))
		defer nc.Close()

		mch := make(chan *nats.Msg, 9)
		sub, _ := nc.ChanSubscribe(nats.NewInbox(), mch)

		var req []byte
		if filter != _EMPTY_ {
			req, _ = json.Marshal(&ConnzOptions{FilterSubject: filter})
		}

		if err := nc.PublishRequest(reqSubj, sub.Subject, req); err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}

		// So we can igniore ourtselves.
		cid, _ := nc.GetClientID()
		sid := nc.ConnectedServerId()

		wt := time.NewTimer(200 * time.Millisecond)
		var conns []*ConnInfo
	LOOP:
		for {
			select {
			case m := <-mch:
				if len(m.Data) == 0 {
					t.Fatalf("No responders")
				}
				cr := parseConnz(m.Data)
				// For account scoped, NumConns and Total should be the same (sans limits and offsets).
				// It Total should not include other accounts since that would leak information about the system.
				if filter == _EMPTY_ && cr.NumConns != cr.Total {
					t.Fatalf("NumConns and Total should be same with account scoped connz, got %+v", cr)
				}
				for _, c := range cr.Conns {
					if c.Name != acc {
						t.Fatalf("Got wrong account: %q vs %q for %+v", acc, c.Account, c)
					}
					if !(c.Cid == cid && cr.ID == sid) {
						conns = append(conns, c)
					}
				}
				wt.Reset(200 * time.Millisecond)
			case <-wt.C:
				break LOOP
			}
		}
		if len(conns) != expected {
			t.Fatalf("Expected to see %d conns but got %d", expected, len(conns))
		}
	}

	doSysRequest := func(acc string, expected int) {
		t.Helper()
		doRequest("$SYS.REQ.SERVER.PING.CONNZ", acc, _EMPTY_, expected)
	}
	doAccRequest := func(acc string, expected int) {
		t.Helper()
		doRequest("$SYS.REQ.ACCOUNT.PING.CONNZ", acc, _EMPTY_, expected)
	}
	doFiltered := func(acc, filter string, expected int) {
		t.Helper()
		doRequest("$SYS.REQ.SERVER.PING.CONNZ", acc, filter, expected)
	}

	doSysRequest("one", 20)
	doAccRequest("one", 20)

	doSysRequest("two", 20)
	doAccRequest("two", 20)

	// Now check filtering.
	doFiltered("one", _EMPTY_, 20)
	doFiltered("one", ">", 20)
	doFiltered("one", "bar", 10)
	doFiltered("two", "bar", 0)
	doFiltered("two", "id.1", 1)
	doFiltered("two", "id.*", 20)
	doFiltered("two", "foo.bar.*", 20)
	doFiltered("two", "foo.>", 20)
}

func TestNoRaceCompressedConnz(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, _ := jsClientConnect(t, s)
	defer nc.Close()

	doRequest := func(compress string) {
		t.Helper()
		m := nats.NewMsg("$SYS.REQ.ACCOUNT.PING.CONNZ")
		m.Header.Add("Accept-Encoding", compress)
		resp, err := nc.RequestMsg(m, time.Second)
		if err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		buf := resp.Data

		// Make sure we have an encoding header.
		ce := resp.Header.Get("Content-Encoding")
		switch strings.ToLower(ce) {
		case "gzip":
			zr, err := gzip.NewReader(bytes.NewReader(buf))
			if err != nil {
				t.Fatalf("Unexpected error: %v", err)
			}
			defer zr.Close()
			buf, err = io.ReadAll(zr)
			if err != nil && err != io.ErrUnexpectedEOF {
				t.Fatalf("Unexpected error: %v", err)
			}
		case "snappy", "s2":
			sr := s2.NewReader(bytes.NewReader(buf))
			buf, err = io.ReadAll(sr)
			if err != nil && err != io.ErrUnexpectedEOF {
				t.Fatalf("Unexpected error: %v", err)
			}
		default:
			t.Fatalf("Unknown content-encoding of %q", ce)
		}

		var cz ServerAPIConnzResponse
		if err := json.Unmarshal(buf, &cz); err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		if cz.Error != nil {
			t.Fatalf("Unexpected error: %+v", cz.Error)
		}
	}

	doRequest("gzip")
	doRequest("snappy")
	doRequest("s2")
}

func TestNoRaceJetStreamClusterExtendedStreamPurge(t *testing.T) {
	for _, st := range []StorageType{FileStorage, MemoryStorage} {
		t.Run(st.String(), func(t *testing.T) {
			c := createJetStreamClusterExplicit(t, "JSC", 3)
			defer c.shutdown()

			nc, js := jsClientConnect(t, c.randomServer())
			defer nc.Close()

			cfg := StreamConfig{
				Name:       "KV",
				Subjects:   []string{"kv.>"},
				Storage:    st,
				Replicas:   2,
				MaxMsgsPer: 100,
			}
			req, err := json.Marshal(cfg)
			if err != nil {
				t.Fatalf("Unexpected error: %v", err)
			}
			// Do manually for now.
			nc.Request(fmt.Sprintf(JSApiStreamCreateT, cfg.Name), req, time.Second)
			c.waitOnStreamLeader("$G", "KV")

			si, err := js.StreamInfo("KV")
			if err != nil {
				t.Fatalf("Unexpected error: %v", err)
			}
			if si == nil || si.Config.Name != "KV" {
				t.Fatalf("StreamInfo is not correct %+v", si)
			}

			for i := 0; i < 1000; i++ {
				js.PublishAsync("kv.foo", []byte("OK")) // 1 * i
				js.PublishAsync("kv.bar", []byte("OK")) // 2 * i
				js.PublishAsync("kv.baz", []byte("OK")) // 3 * i
			}
			// First is 2700, last is 3000
			for i := 0; i < 700; i++ {
				js.PublishAsync(fmt.Sprintf("kv.%d", i+1), []byte("OK"))
			}
			// Now first is 2700, last is 3700
			select {
			case <-js.PublishAsyncComplete():
			case <-time.After(10 * time.Second):
				t.Fatalf("Did not receive completion signal")
			}

			si, err = js.StreamInfo("KV")
			if err != nil {
				t.Fatalf("Unexpected error: %v", err)
			}
			if si.State.Msgs != 1000 {
				t.Fatalf("Expected %d msgs, got %d", 1000, si.State.Msgs)
			}

			shouldFail := func(preq *JSApiStreamPurgeRequest) {
				req, _ := json.Marshal(preq)
				resp, err := nc.Request(fmt.Sprintf(JSApiStreamPurgeT, "KV"), req, time.Second)
				if err != nil {
					t.Fatalf("Unexpected error: %v", err)
				}
				var pResp JSApiStreamPurgeResponse
				if err = json.Unmarshal(resp.Data, &pResp); err != nil {
					t.Fatalf("Unexpected error: %v", err)
				}
				if pResp.Success || pResp.Error == nil {
					t.Fatalf("Expected an error response but got none")
				}
			}

			// Sequence and Keep should be mutually exclusive.
			shouldFail(&JSApiStreamPurgeRequest{Sequence: 10, Keep: 10})

			purge := func(preq *JSApiStreamPurgeRequest, newTotal uint64) {
				t.Helper()
				req, _ := json.Marshal(preq)
				resp, err := nc.Request(fmt.Sprintf(JSApiStreamPurgeT, "KV"), req, time.Second)
				if err != nil {
					t.Fatalf("Unexpected error: %v", err)
				}
				var pResp JSApiStreamPurgeResponse
				if err = json.Unmarshal(resp.Data, &pResp); err != nil {
					t.Fatalf("Unexpected error: %v", err)
				}
				if !pResp.Success || pResp.Error != nil {
					t.Fatalf("Got a bad response %+v", pResp)
				}
				si, err = js.StreamInfo("KV")
				if err != nil {
					t.Fatalf("Unexpected error: %v", err)
				}
				if si.State.Msgs != newTotal {
					t.Fatalf("Expected total after purge to be %d but got %d", newTotal, si.State.Msgs)
				}
			}
			expectLeft := func(subject string, expected uint64) {
				t.Helper()
				ci, err := js.AddConsumer("KV", &nats.ConsumerConfig{Durable: "dlc", FilterSubject: subject, AckPolicy: nats.AckExplicitPolicy})
				if err != nil {
					t.Fatalf("Unexpected error: %v", err)
				}
				defer js.DeleteConsumer("KV", "dlc")
				if ci.NumPending != expected {
					t.Fatalf("Expected %d remaining but got %d", expected, ci.NumPending)
				}
			}

			purge(&JSApiStreamPurgeRequest{Subject: "kv.foo"}, 900)
			expectLeft("kv.foo", 0)

			purge(&JSApiStreamPurgeRequest{Subject: "kv.bar", Keep: 1}, 801)
			expectLeft("kv.bar", 1)

			purge(&JSApiStreamPurgeRequest{Subject: "kv.baz", Sequence: 2851}, 751)
			expectLeft("kv.baz", 50)

			purge(&JSApiStreamPurgeRequest{Subject: "kv.*"}, 0)

			// RESET
			js.DeleteStream("KV")
			// Do manually for now.
			nc.Request(fmt.Sprintf(JSApiStreamCreateT, cfg.Name), req, time.Second)
			c.waitOnStreamLeader("$G", "KV")

			if _, err := js.StreamInfo("KV"); err != nil {
				t.Fatalf("Unexpected error: %v", err)
			}
			// Put in 100.
			for i := 0; i < 100; i++ {
				js.PublishAsync("kv.foo", []byte("OK"))
			}
			select {
			case <-js.PublishAsyncComplete():
			case <-time.After(time.Second):
				t.Fatalf("Did not receive completion signal")
			}
			purge(&JSApiStreamPurgeRequest{Subject: "kv.foo", Keep: 10}, 10)
			purge(&JSApiStreamPurgeRequest{Subject: "kv.foo", Keep: 10}, 10)
			expectLeft("kv.foo", 10)

			// RESET AGAIN
			js.DeleteStream("KV")
			// Do manually for now.
			nc.Request(fmt.Sprintf(JSApiStreamCreateT, cfg.Name), req, time.Second)
			c.waitOnStreamLeader("$G", "KV")

			if _, err := js.StreamInfo("KV"); err != nil {
				t.Fatalf("Unexpected error: %v", err)
			}
			// Put in 100.
			for i := 0; i < 100; i++ {
				js.Publish("kv.foo", []byte("OK"))
			}
			purge(&JSApiStreamPurgeRequest{Keep: 10}, 10)
			expectLeft(">", 10)

			// RESET AGAIN
			js.DeleteStream("KV")
			// Do manually for now.
			nc.Request(fmt.Sprintf(JSApiStreamCreateT, cfg.Name), req, time.Second)
			if _, err := js.StreamInfo("KV"); err != nil {
				t.Fatalf("Unexpected error: %v", err)
			}
			// Put in 100.
			for i := 0; i < 100; i++ {
				js.Publish("kv.foo", []byte("OK"))
			}
			purge(&JSApiStreamPurgeRequest{Sequence: 90}, 11) // Up to 90 so we keep that, hence the 11.
			expectLeft(">", 11)
		})
	}
}

func TestNoRaceJetStreamFileStoreCompaction(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	cfg := &nats.StreamConfig{
		Name:              "KV",
		Subjects:          []string{"KV.>"},
		MaxMsgsPerSubject: 1,
	}
	if _, err := js.AddStream(cfg); err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	toSend := 10_000
	data := make([]byte, 4*1024)
	crand.Read(data)

	// First one.
	js.PublishAsync("KV.FM", data)

	for i := 0; i < toSend; i++ {
		js.PublishAsync(fmt.Sprintf("KV.%d", i+1), data)
	}
	// Do again and overwrite the previous batch.
	for i := 0; i < toSend; i++ {
		js.PublishAsync(fmt.Sprintf("KV.%d", i+1), data)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(10 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	// Now check by hand the utilization level.
	mset, err := s.GlobalAccount().lookupStream("KV")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	total, used, _ := mset.Store().Utilization()
	if pu := 100.0 * float32(used) / float32(total); pu < 80.0 {
		t.Fatalf("Utilization is less than 80%%, got %.2f", pu)
	}
}

func TestNoRaceJetStreamEncryptionEnabledOnRestartWithExpire(t *testing.T) {
	conf := createConfFile(t, []byte(fmt.Sprintf(`
		listen: 127.0.0.1:-1
		jetstream {
			store_dir = %q
		}
	`, t.TempDir())))

	s, _ := RunServerWithConfig(conf)
	defer s.Shutdown()

	config := s.JetStreamConfig()
	if config == nil {
		t.Fatalf("Expected config but got none")
	}
	defer removeDir(t, config.StoreDir)

	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	toSend := 10_000

	cfg := &nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo", "bar"},
		MaxMsgs:  int64(toSend),
	}
	if _, err := js.AddStream(cfg); err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	data := make([]byte, 4*1024) // 4K payload
	crand.Read(data)

	for i := 0; i < toSend; i++ {
		js.PublishAsync("foo", data)
		js.PublishAsync("bar", data)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	_, err := js.AddConsumer("TEST", &nats.ConsumerConfig{Durable: "dlc", AckPolicy: nats.AckExplicitPolicy})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	// Restart
	nc.Close()
	s.Shutdown()

	ncs := fmt.Sprintf("\nlisten: 127.0.0.1:-1\njetstream: {key: %q, store_dir: %q}\n", "s3cr3t!", config.StoreDir)
	conf = createConfFile(t, []byte(ncs))

	// Try to drain entropy to see if effects startup time.
	drain := make([]byte, 32*1024*1024) // Pull 32Mb of crypto rand.
	crand.Read(drain)

	start := time.Now()
	s, _ = RunServerWithConfig(conf)
	defer s.Shutdown()
	dd := time.Since(start)
	if dd > 5*time.Second {
		t.Fatalf("Restart took longer than expected: %v", dd)
	}
}

// This test was from Ivan K. and showed a bug in the filestore implementation.
// This is skipped by default since it takes >40s to run.
func TestNoRaceJetStreamOrderedConsumerMissingMsg(t *testing.T) {
	// Uncomment to run. Needs to be on a big machine. Do not want as part of Travis tests atm.
	skip(t)

	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	if _, err := js.AddStream(&nats.StreamConfig{
		Name:     "benchstream",
		Subjects: []string{"testsubject"},
		Replicas: 1,
	}); err != nil {
		t.Fatalf("add stream failed: %s", err)
	}

	total := 1_000_000

	numSubs := 10
	ch := make(chan struct{}, numSubs)
	wg := sync.WaitGroup{}
	wg.Add(numSubs)
	errCh := make(chan error, 1)
	for i := 0; i < numSubs; i++ {
		nc, js := jsClientConnect(t, s)
		defer nc.Close()
		go func(nc *nats.Conn, js nats.JetStreamContext) {
			defer wg.Done()
			received := 0
			_, err := js.Subscribe("testsubject", func(m *nats.Msg) {
				meta, _ := m.Metadata()
				if meta.Sequence.Consumer != meta.Sequence.Stream {
					nc.Close()
					errCh <- fmt.Errorf("Bad meta: %+v", meta)
				}
				received++
				if received == total {
					ch <- struct{}{}
				}
			}, nats.OrderedConsumer())
			if err != nil {
				select {
				case errCh <- fmt.Errorf("Error creating sub: %v", err):
				default:
				}

			}
		}(nc, js)
	}
	wg.Wait()
	select {
	case e := <-errCh:
		t.Fatal(e)
	default:
	}

	payload := make([]byte, 500)
	for i := 1; i <= total; i++ {
		js.PublishAsync("testsubject", payload)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(10 * time.Second):
		t.Fatalf("Did not send all messages")
	}

	// Now wait for consumers to be done:
	for i := 0; i < numSubs; i++ {
		select {
		case <-ch:
		case <-time.After(10 * time.Second):
			t.Fatal("Did not receive all messages for all consumers in time")
		}
	}

}

// Issue #2488 - Bad accounting, can not reproduce the stalled consumers after last several PRs.
// Issue did show bug in ack logic for no-ack and interest based retention.
func TestNoRaceJetStreamClusterInterestPolicyAckNone(t *testing.T) {
	for _, test := range []struct {
		name    string
		durable string
	}{
		{"durable", "dlc"},
		{"ephemeral", _EMPTY_},
	} {
		t.Run(test.name, func(t *testing.T) {
			c := createJetStreamClusterExplicit(t, "R3S", 3)
			defer c.shutdown()

			// Client based API
			nc, js := jsClientConnect(t, c.randomServer())
			defer nc.Close()

			_, err := js.AddStream(&nats.StreamConfig{
				Name:      "cluster",
				Subjects:  []string{"cluster.*"},
				Retention: nats.InterestPolicy,
				Discard:   nats.DiscardOld,
				Replicas:  3,
			})
			if err != nil {
				t.Fatalf("Unexpected error: %v", err)
			}

			var received uint32
			mh := func(m *nats.Msg) {
				atomic.AddUint32(&received, 1)
			}

			opts := []nats.SubOpt{nats.DeliverNew(), nats.AckNone()}
			if test.durable != _EMPTY_ {
				opts = append(opts, nats.Durable(test.durable))
			}
			_, err = js.Subscribe("cluster.created", mh, opts...)
			if err != nil {
				t.Fatalf("Unexpected error: %v", err)
			}

			msg := []byte("ACK ME")
			const total = uint32(1_000)
			for i := 0; i < int(total); i++ {
				if _, err := js.Publish("cluster.created", msg); err != nil {
					t.Fatalf("Unexpected error: %v", err)
				}
				//time.Sleep(100 * time.Microsecond)
			}

			// Wait for all messages to be received.
			checkFor(t, 2*time.Second, 100*time.Millisecond, func() error {
				r := atomic.LoadUint32(&received)
				if r == total {
					return nil
				}
				return fmt.Errorf("Received only %d out of %d", r, total)
			})

			checkFor(t, 5*time.Second, 100*time.Millisecond, func() error {
				si, err := js.StreamInfo("cluster")
				if err != nil {
					t.Fatalf("Error getting stream info: %v", err)
				}
				if si.State.Msgs != 0 {
					return fmt.Errorf("Expected no messages, got %d", si.State.Msgs)
				}
				return nil
			})
		})
	}
}

// There was a bug in the filestore compact code that would cause a store
// with JSExpectedLastSubjSeq to fail with "wrong last sequence: 0"
func TestNoRaceJetStreamLastSubjSeqAndFilestoreCompact(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	// Client based API
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:              "MQTT_sess",
		Subjects:          []string{"MQTT.sess.>"},
		Storage:           nats.FileStorage,
		Retention:         nats.LimitsPolicy,
		Replicas:          1,
		MaxMsgsPerSubject: 1,
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	firstPayload := make([]byte, 40)
	secondPayload := make([]byte, 380)
	for iter := 0; iter < 2; iter++ {
		for i := 0; i < 4000; i++ {
			subj := "MQTT.sess." + getHash(fmt.Sprintf("client_%d", i))
			pa, err := js.Publish(subj, firstPayload)
			if err != nil {
				t.Fatalf("Error on publish: %v", err)
			}
			m := nats.NewMsg(subj)
			m.Data = secondPayload
			eseq := strconv.FormatInt(int64(pa.Sequence), 10)
			m.Header.Set(JSExpectedLastSubjSeq, eseq)
			if _, err := js.PublishMsg(m); err != nil {
				t.Fatalf("Error on publish (iter=%v seq=%v): %v", iter+1, pa.Sequence, err)
			}
		}
	}
}

// Issue #2548
func TestNoRaceJetStreamClusterMemoryStreamConsumerRaftGrowth(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "memory-leak",
		Subjects:  []string{"memory-leak"},
		Retention: nats.LimitsPolicy,
		MaxMsgs:   1000,
		Discard:   nats.DiscardOld,
		MaxAge:    time.Minute,
		Storage:   nats.MemoryStorage,
		Replicas:  3,
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	_, err = js.QueueSubscribe("memory-leak", "q1", func(msg *nats.Msg) {
		time.Sleep(1 * time.Second)
		msg.AckSync()
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	// Send 10k (Must be > 8192 which is compactNumMin from monitorConsumer.
	msg := []byte("NATS is a connective technology that powers modern distributed systems.")
	for i := 0; i < 10_000; i++ {
		if _, err := js.Publish("memory-leak", msg); err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
	}

	// We will verify here that the underlying raft layer for the leader is not > 8192
	cl := c.consumerLeader("$G", "memory-leak", "q1")
	mset, err := cl.GlobalAccount().lookupStream("memory-leak")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	o := mset.lookupConsumer("q1")
	if o == nil {
		t.Fatalf("Error looking up consumer %q", "q1")
	}
	node := o.raftNode().(*raft)
	checkFor(t, 10*time.Second, 100*time.Millisecond, func() error {
		if ms := node.wal.(*memStore); ms.State().Msgs > 8192 {
			return fmt.Errorf("Did not compact the raft memory WAL")
		}
		return nil
	})
}

func TestNoRaceJetStreamClusterCorruptWAL(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	if _, err := js.AddStream(&nats.StreamConfig{Name: "TEST", Subjects: []string{"foo"}, Replicas: 3}); err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	sub, err := js.PullSubscribe("foo", "dlc")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	numMsgs := 1000
	for i := 0; i < numMsgs; i++ {
		js.PublishAsync("foo", []byte("WAL"))
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	for i, m := range fetchMsgs(t, sub, 200, 5*time.Second) {
		// Ack first 50 and every other even on after that..
		if i < 50 || i%2 == 1 {
			m.AckSync()
		}
	}
	// Make sure acks processed.
	time.Sleep(200 * time.Millisecond)
	nc.Close()

	// Check consumer consistency.
	checkConsumerWith := func(delivered, ackFloor uint64, ackPending int) {
		t.Helper()
		nc, js := jsClientConnect(t, c.randomServer())
		defer nc.Close()

		checkFor(t, 5*time.Second, 100*time.Millisecond, func() error {
			ci, err := js.ConsumerInfo("TEST", "dlc")
			if err != nil {
				return fmt.Errorf("Unexpected error: %v", err)
			}
			if ci.Delivered.Consumer != ci.Delivered.Stream || ci.Delivered.Consumer != delivered {
				return fmt.Errorf("Expected %d for delivered, got %+v", delivered, ci.Delivered)
			}
			if ci.AckFloor.Consumer != ci.AckFloor.Stream || ci.AckFloor.Consumer != ackFloor {
				return fmt.Errorf("Expected %d for ack floor, got %+v", ackFloor, ci.AckFloor)
			}
			nm := uint64(numMsgs)
			if ci.NumPending != nm-delivered {
				return fmt.Errorf("Expected num pending to be %d, got %d", nm-delivered, ci.NumPending)
			}
			if ci.NumAckPending != ackPending {
				return fmt.Errorf("Expected num ack pending to be %d, got %d", ackPending, ci.NumAckPending)
			}
			return nil
		})
	}

	checkConsumer := func() {
		t.Helper()
		checkConsumerWith(200, 50, 75)
	}

	checkConsumer()

	// Grab the consumer leader.
	cl := c.consumerLeader("$G", "TEST", "dlc")
	mset, err := cl.GlobalAccount().lookupStream("TEST")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	o := mset.lookupConsumer("dlc")
	if o == nil {
		t.Fatalf("Error looking up consumer %q", "dlc")
	}
	// Grab underlying raft node and the WAL (filestore) and we will attempt to "corrupt" it.
	node := o.raftNode().(*raft)
	// We are doing a stop here to prevent the internal consumer snapshot from happening on exit
	node.Stop()
	fs := node.wal.(*fileStore)
	fcfg, cfg := fs.fcfg, fs.cfg.StreamConfig
	// Stop all the servers.
	c.stopAll()

	// Manipulate directly with cluster down.
	fs, err = newFileStore(fcfg, cfg)
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	state := fs.State()
	sm, err := fs.LoadMsg(state.LastSeq, nil)
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	ae, err := node.decodeAppendEntry(sm.msg, nil, _EMPTY_)
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	dentry := func(dseq, sseq, dc uint64, ts int64) []byte {
		b := make([]byte, 4*binary.MaxVarintLen64+1)
		b[0] = byte(updateDeliveredOp)
		n := 1
		n += binary.PutUvarint(b[n:], dseq)
		n += binary.PutUvarint(b[n:], sseq)
		n += binary.PutUvarint(b[n:], dc)
		n += binary.PutVarint(b[n:], ts)
		return b[:n]
	}

	// Let's put a non-contigous AppendEntry into the system.
	ae.pindex += 10
	// Add in delivered record.
	ae.entries = []*Entry{{EntryNormal, dentry(1000, 1000, 1, time.Now().UnixNano())}}
	encoded, err := ae.encode(nil)
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	if _, _, err := fs.StoreMsg(_EMPTY_, nil, encoded); err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	fs.Stop()

	c.restartAllSamePorts()
	c.waitOnStreamLeader("$G", "TEST")
	c.waitOnConsumerLeader("$G", "TEST", "dlc")

	checkConsumer()

	// Now we will truncate out the WAL out from underneath the leader.
	// Grab the consumer leader.

	nc, js = jsClientConnect(t, c.randomServer())
	defer nc.Close()

	cl = c.consumerLeader("$G", "TEST", "dlc")
	mset, err = cl.GlobalAccount().lookupStream("TEST")
	require_NoError(t, err)
	o = mset.lookupConsumer("dlc")
	require_NoError(t, err)

	// Grab underlying raft node and the WAL (filestore) and truncate it.
	// This will simulate the WAL losing state due to truncate and we want to make sure it recovers.

	fs = o.raftNode().(*raft).wal.(*fileStore)
	state = fs.State()
	err = fs.Truncate(state.FirstSeq)
	require_True(t, err == nil || err == ErrInvalidSequence)
	state = fs.State()

	sub, err = js.PullSubscribe("foo", "dlc")
	require_NoError(t, err)

	// This will cause us to stepdown and truncate our WAL.
	sub.Fetch(100)
	c.waitOnConsumerLeader("$G", "TEST", "dlc")
	// We can't trust the results sans that we have a leader back in place and the ackFloor.
	ci, err := js.ConsumerInfo("TEST", "dlc")
	require_NoError(t, err)
	if ci.AckFloor.Consumer != ci.AckFloor.Stream || ci.AckFloor.Consumer != 50 {
		t.Fatalf("Expected %d for ack floor, got %+v", 50, ci.AckFloor)
	}
}

func TestNoRaceJetStreamClusterInterestRetentionDeadlock(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	// Client based API
	s := c.randomServer()
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	// This can trigger deadlock with current architecture.
	// If stream is !limitsRetention and consumer is DIRECT and ack none we will try to place the msg seq
	// onto a chan for the stream to consider removing. All conditions above must hold to trigger.

	// We will attempt to trigger here with a stream mirror setup which uses and R=1 DIRECT consumer to replicate msgs.
	_, err := js.AddStream(&nats.StreamConfig{Name: "S", Retention: nats.InterestPolicy, Storage: nats.MemoryStorage})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	// Create a mirror which will create the consumer profile to trigger.
	_, err = js.AddStream(&nats.StreamConfig{Name: "M", Mirror: &nats.StreamSource{Name: "S"}})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	// Queue up alot of messages.
	numRequests := 20_000
	for i := 0; i < numRequests; i++ {
		js.PublishAsync("S", []byte("Q"))
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	checkFor(t, 5*time.Second, 100*time.Millisecond, func() error {
		si, err := js.StreamInfo("S")
		if err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
		if si.State.Msgs != 0 {
			return fmt.Errorf("Expected 0 msgs, got state: %+v", si.State)
		}
		return nil
	})
}

func TestNoRaceJetStreamClusterMaxConsumersAndDirect(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	// Client based API
	s := c.randomServer()
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	// We want to max sure max consumer limits do not affect mirrors or sources etc.
	_, err := js.AddStream(&nats.StreamConfig{Name: "S", Storage: nats.MemoryStorage, MaxConsumers: 1})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	var mirrors []string
	for i := 0; i < 10; i++ {
		// Create a mirror.
		mname := fmt.Sprintf("M-%d", i+1)
		mirrors = append(mirrors, mname)
		_, err = js.AddStream(&nats.StreamConfig{Name: mname, Mirror: &nats.StreamSource{Name: "S"}})
		if err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
	}

	// Queue up messages.
	numRequests := 20
	for i := 0; i < numRequests; i++ {
		js.Publish("S", []byte("Q"))
	}

	checkFor(t, 5*time.Second, 100*time.Millisecond, func() error {
		for _, mname := range mirrors {
			si, err := js.StreamInfo(mname)
			if err != nil {
				t.Fatalf("Unexpected error: %v", err)
			}
			if si.State.Msgs != uint64(numRequests) {
				return fmt.Errorf("Expected %d msgs for %q, got state: %+v", numRequests, mname, si.State)
			}
		}
		return nil
	})
}

// Make sure when we try to hard reset a stream state in a cluster that we also re-create the consumers.
func TestNoRaceJetStreamClusterStreamReset(t *testing.T) {
	// Speed up raft
	omin, omax, ohb := minElectionTimeout, maxElectionTimeout, hbInterval
	minElectionTimeout = 250 * time.Millisecond
	maxElectionTimeout = time.Second
	hbInterval = 50 * time.Millisecond
	defer func() {
		minElectionTimeout = omin
		maxElectionTimeout = omax
		hbInterval = ohb
	}()

	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	// Client based API
	s := c.randomServer()
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "TEST",
		Subjects:  []string{"foo.*"},
		Replicas:  2,
		Retention: nats.WorkQueuePolicy,
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	numRequests := 20
	for i := 0; i < numRequests; i++ {
		js.Publish("foo.created", []byte("REQ"))
	}

	// Durable.
	sub, err := js.SubscribeSync("foo.created", nats.Durable("d1"))
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	defer sub.Unsubscribe()

	si, err := js.StreamInfo("TEST")
	require_NoError(t, err)
	require_True(t, si.State.Msgs == uint64(numRequests))

	// Let settle a bit for Go routine checks.
	time.Sleep(500 * time.Millisecond)

	// Grab number go routines.
	base := runtime.NumGoroutine()

	// Make the consumer busy here by async sending a bunch of messages.
	for i := 0; i < numRequests*10; i++ {
		js.PublishAsync("foo.created", []byte("REQ"))
	}

	// Grab a server that is the consumer leader for the durable.
	cl := c.consumerLeader("$G", "TEST", "d1")
	mset, err := cl.GlobalAccount().lookupStream("TEST")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	// Do a hard reset here by hand.
	mset.resetClusteredState(nil)

	// Wait til we have the consumer leader re-elected.
	c.waitOnConsumerLeader("$G", "TEST", "d1")

	// Make sure we can get the consumer info eventually.
	checkFor(t, 5*time.Second, 200*time.Millisecond, func() error {
		_, err := js.ConsumerInfo("TEST", "d1", nats.MaxWait(250*time.Millisecond))
		return err
	})

	checkFor(t, 5*time.Second, 200*time.Millisecond, func() error {
		if after := runtime.NumGoroutine(); base > after {
			return fmt.Errorf("Expected %d go routines, got %d", base, after)
		}
		return nil
	})

	// Simulate a low level write error on our consumer and make sure we can recover etc.
	checkFor(t, 10*time.Second, 200*time.Millisecond, func() error {
		if cl = c.consumerLeader("$G", "TEST", "d1"); cl != nil {
			return nil
		}
		return errors.New("waiting on consumer leader")
	})

	mset, err = cl.GlobalAccount().lookupStream("TEST")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	o := mset.lookupConsumer("d1")
	if o == nil {
		t.Fatalf("Did not retrieve consumer")
	}
	node := o.raftNode().(*raft)
	if node == nil {
		t.Fatalf("could not retrieve the raft node for consumer")
	}

	nc.Close()
	node.setWriteErr(io.ErrShortWrite)

	c.stopAll()
	c.restartAll()

	c.waitOnStreamLeader("$G", "TEST")
	c.waitOnConsumerLeader("$G", "TEST", "d1")
}

// Reports of high cpu on compaction for a KV store.
func TestNoRaceJetStreamKeyValueCompaction(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	// Client based API
	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	kv, err := js.CreateKeyValue(&nats.KeyValueConfig{
		Bucket:   "COMPACT",
		Replicas: 3,
	})
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	value := strings.Repeat("A", 128*1024)
	for i := 0; i < 5_000; i++ {
		key := fmt.Sprintf("K-%d", rand.Intn(256)+1)
		if _, err := kv.PutString(key, value); err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
	}
}

// Trying to recreate an issue rip saw with KV and server restarts complaining about
// mismatch for a few minutes and growing memory.
func TestNoRaceJetStreamClusterStreamSeqMismatchIssue(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	// Client based API
	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	kv, err := js.CreateKeyValue(&nats.KeyValueConfig{
		Bucket:   "MM",
		Replicas: 3,
		TTL:      500 * time.Millisecond,
	})
	require_NoError(t, err)

	for i := 1; i <= 10; i++ {
		if _, err := kv.PutString("k", "1"); err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
	}
	// Close in case we are connected here. Will recreate.
	nc.Close()

	// Shutdown a non-leader.
	s := c.randomNonStreamLeader("$G", "KV_MM")
	s.Shutdown()

	nc, js = jsClientConnect(t, c.randomServer())
	defer nc.Close()

	kv, err = js.KeyValue("MM")
	require_NoError(t, err)

	// Now change the state of the stream such that we have to do a compact upon restart
	// of the downed server.
	for i := 1; i <= 10; i++ {
		if _, err := kv.PutString("k", "2"); err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
	}

	// Raft could save us here so need to run a compact on the leader.
	snapshotLeader := func() {
		sl := c.streamLeader("$G", "KV_MM")
		if sl == nil {
			t.Fatalf("Did not get the leader")
		}
		mset, err := sl.GlobalAccount().lookupStream("KV_MM")
		require_NoError(t, err)
		node := mset.raftNode()
		if node == nil {
			t.Fatalf("Could not get stream group")
		}
		if err := node.InstallSnapshot(mset.stateSnapshot()); err != nil {
			t.Fatalf("Error installing snapshot: %v", err)
		}
	}

	// Now wait for expiration
	time.Sleep(time.Second)

	snapshotLeader()

	s = c.restartServer(s)
	c.waitOnServerCurrent(s)

	// We want to make sure we do not reset the raft state on a catchup due to no request yield.
	// Bug was if we did not actually request any help from snapshot we did not set mset.lseq properly.
	// So when we send next batch that would cause raft reset due to cluster reset for our stream.
	mset, err := s.GlobalAccount().lookupStream("KV_MM")
	require_NoError(t, err)

	for i := 1; i <= 10; i++ {
		if _, err := kv.PutString("k1", "X"); err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
	}

	c.waitOnStreamCurrent(s, "$G", "KV_MM")

	// Make sure we did not reset our stream.
	msetNew, err := s.GlobalAccount().lookupStream("KV_MM")
	require_NoError(t, err)
	if msetNew != mset {
		t.Fatalf("Stream was reset")
	}
}

func TestNoRaceJetStreamClusterStreamDropCLFS(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	// Client based API
	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	kv, err := js.CreateKeyValue(&nats.KeyValueConfig{
		Bucket:   "CLFS",
		Replicas: 3,
	})
	require_NoError(t, err)

	// Will work
	_, err = kv.Create("k.1", []byte("X"))
	require_NoError(t, err)
	// Drive up CLFS state on leader.
	for i := 0; i < 10; i++ {
		_, err = kv.Create("k.1", []byte("X"))
		require_Error(t, err)
	}
	// Bookend with new key success.
	_, err = kv.Create("k.2", []byte("Z"))
	require_NoError(t, err)

	// Close in case we are connected here. Will recreate.
	nc.Close()

	// Shutdown, which will also clear clfs.
	s := c.randomNonStreamLeader("$G", "KV_CLFS")
	s.Shutdown()

	nc, js = jsClientConnect(t, c.randomServer())
	defer nc.Close()

	kv, err = js.KeyValue("CLFS")
	require_NoError(t, err)

	// Drive up CLFS state on leader.
	for i := 0; i < 10; i++ {
		_, err = kv.Create("k.1", []byte("X"))
		require_Error(t, err)
	}

	sl := c.streamLeader("$G", "KV_CLFS")
	if sl == nil {
		t.Fatalf("Did not get the leader")
	}
	mset, err := sl.GlobalAccount().lookupStream("KV_CLFS")
	require_NoError(t, err)
	node := mset.raftNode()
	if node == nil {
		t.Fatalf("Could not get stream group")
	}
	if err := node.InstallSnapshot(mset.stateSnapshot()); err != nil {
		t.Fatalf("Error installing snapshot: %v", err)
	}

	_, err = kv.Create("k.3", []byte("ZZZ"))
	require_NoError(t, err)

	s = c.restartServer(s)
	c.waitOnServerCurrent(s)

	mset, err = s.GlobalAccount().lookupStream("KV_CLFS")
	require_NoError(t, err)

	_, err = kv.Create("k.4", []byte("YYY"))
	require_NoError(t, err)

	c.waitOnStreamCurrent(s, "$G", "KV_CLFS")

	// Make sure we did not reset our stream.
	msetNew, err := s.GlobalAccount().lookupStream("KV_CLFS")
	require_NoError(t, err)
	if msetNew != mset {
		t.Fatalf("Stream was reset")
	}
}

func TestNoRaceJetStreamMemstoreWithLargeInteriorDeletes(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	// Client for API requests.
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:              "TEST",
		Subjects:          []string{"foo", "bar"},
		MaxMsgsPerSubject: 1,
		Storage:           nats.MemoryStorage,
	})
	require_NoError(t, err)

	acc, err := s.lookupAccount("$G")
	require_NoError(t, err)
	mset, err := acc.lookupStream("TEST")
	require_NoError(t, err)

	msg := []byte("Hello World!")
	if _, err := js.PublishAsync("foo", msg); err != nil {
		t.Fatalf("Unexpected publish error: %v", err)
	}
	for i := 1; i <= 1_000_000; i++ {
		if _, err := js.PublishAsync("bar", msg); err != nil {
			t.Fatalf("Unexpected publish error: %v", err)
		}
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	now := time.Now()
	ss := mset.stateWithDetail(true)
	// Before the fix the snapshot for this test would be > 200ms on my setup.
	if elapsed := time.Since(now); elapsed > 100*time.Millisecond {
		t.Fatalf("Took too long to snapshot: %v", elapsed)
	} else if elapsed > 50*time.Millisecond {
		t.Logf("WRN: Took longer than usual to snapshot: %v", elapsed)
	}

	if ss.Msgs != 2 || ss.FirstSeq != 1 || ss.LastSeq != 1_000_001 || ss.NumDeleted != 999999 {
		// To not print out on error.
		ss.Deleted = nil
		t.Fatalf("Bad State: %+v", ss)
	}
}

// This is related to an issue reported where we were exhausting threads by trying to
// cleanup too many consumers at the same time.
// https://github.com/nats-io/nats-server/issues/2742
func TestNoRaceJetStreamConsumerFileStoreConcurrentDiskIO(t *testing.T) {
	storeDir := t.TempDir()

	// Artificially adjust our environment for this test.
	gmp := runtime.GOMAXPROCS(32)
	defer runtime.GOMAXPROCS(gmp)

	maxT := debug.SetMaxThreads(1050) // 1024 now
	defer debug.SetMaxThreads(maxT)

	fs, err := newFileStore(FileStoreConfig{StoreDir: storeDir}, StreamConfig{Name: "MT", Storage: FileStorage})
	require_NoError(t, err)
	defer fs.Stop()

	startCh := make(chan bool)
	var wg sync.WaitGroup
	var swg sync.WaitGroup

	ts := time.Now().UnixNano()

	// Create 1000 consumerStores
	n := 1000
	swg.Add(n)

	for i := 1; i <= n; i++ {
		name := fmt.Sprintf("o%d", i)
		o, err := fs.ConsumerStore(name, &ConsumerConfig{AckPolicy: AckExplicit})
		require_NoError(t, err)
		wg.Add(1)
		swg.Done()

		go func() {
			defer wg.Done()
			// Will make everyone run concurrently.
			<-startCh
			o.UpdateDelivered(22, 22, 1, ts)
			buf, _ := o.(*consumerFileStore).encodeState()
			o.(*consumerFileStore).writeState(buf)
			o.Delete()
		}()
	}

	swg.Wait()
	close(startCh)
	wg.Wait()
}

func TestNoRaceJetStreamClusterHealthz(t *testing.T) {
	c := createJetStreamCluster(t, jsClusterAccountsTempl, "HZ", _EMPTY_, 3, 23033, true)
	defer c.shutdown()

	nc1, js1 := jsClientConnect(t, c.randomServer(), nats.UserInfo("one", "p"))
	defer nc1.Close()

	nc2, js2 := jsClientConnect(t, c.randomServer(), nats.UserInfo("two", "p"))
	defer nc2.Close()

	var err error
	for _, sname := range []string{"foo", "bar", "baz"} {
		_, err = js1.AddStream(&nats.StreamConfig{Name: sname, Replicas: 3})
		require_NoError(t, err)
		_, err = js2.AddStream(&nats.StreamConfig{Name: sname, Replicas: 3})
		require_NoError(t, err)
	}
	// R1
	_, err = js1.AddStream(&nats.StreamConfig{Name: "r1", Replicas: 1})
	require_NoError(t, err)

	// Now shutdown then send a bunch of data.
	s := c.servers[0]
	s.Shutdown()

	for i := 0; i < 5_000; i++ {
		_, err = js1.PublishAsync("foo", []byte("OK"))
		require_NoError(t, err)
		_, err = js2.PublishAsync("bar", []byte("OK"))
		require_NoError(t, err)
	}
	select {
	case <-js1.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}
	select {
	case <-js2.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	s = c.restartServer(s)
	opts := s.getOpts()
	opts.HTTPHost = "127.0.0.1"
	opts.HTTPPort = 11222
	err = s.StartMonitoring()
	require_NoError(t, err)
	url := fmt.Sprintf("http://127.0.0.1:%d/healthz", opts.HTTPPort)

	getHealth := func() (int, *HealthStatus) {
		resp, err := http.Get(url)
		require_NoError(t, err)
		defer resp.Body.Close()
		body, err := io.ReadAll(resp.Body)
		require_NoError(t, err)
		var hs HealthStatus
		err = json.Unmarshal(body, &hs)
		require_NoError(t, err)
		return resp.StatusCode, &hs
	}

	errors := 0
	checkFor(t, 20*time.Second, 100*time.Millisecond, func() error {
		code, hs := getHealth()
		if code >= 200 && code < 300 {
			return nil
		}
		errors++
		return fmt.Errorf("Got %d status with %+v", code, hs)
	})
	if errors == 0 {
		t.Fatalf("Expected to have some errors until we became current, got none")
	}
}

// Test that we can receive larger messages with stream subject details.
// Also test that we will fail at some point and the user can fall back to
// an orderedconsumer like we do with watch for KV Keys() call.
func TestNoRaceJetStreamStreamInfoSubjectDetailsLimits(t *testing.T) {
	conf := createConfFile(t, []byte(fmt.Sprintf(`
		listen: 127.0.0.1:-1
		jetstream {
			store_dir = %q
		}
		accounts: {
		  default: {
			jetstream: true
			users: [ {user: me, password: pwd} ]
			limits { max_payload: 512 }
		  }
		}
	`, t.TempDir())))

	s, _ := RunServerWithConfig(conf)
	if config := s.JetStreamConfig(); config != nil {
		defer removeDir(t, config.StoreDir)
	}
	defer s.Shutdown()

	nc, js := jsClientConnect(t, s, nats.UserInfo("me", "pwd"))
	defer nc.Close()

	// Make sure to flush so we process the 2nd INFO.
	nc.Flush()

	// Make sure we cannot send larger than 512 bytes.
	// But we can receive larger.
	sub, err := nc.SubscribeSync("foo")
	require_NoError(t, err)
	err = nc.Publish("foo", []byte(strings.Repeat("A", 600)))
	require_Error(t, err, nats.ErrMaxPayload)
	sub.Unsubscribe()

	_, err = js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"*", "X.*"},
	})
	require_NoError(t, err)

	n := JSMaxSubjectDetails
	for i := 0; i < n; i++ {
		_, err := js.PublishAsync(fmt.Sprintf("X.%d", i), []byte("OK"))
		require_NoError(t, err)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	// Need to grab StreamInfo by hand for now.
	req, err := json.Marshal(&JSApiStreamInfoRequest{SubjectsFilter: "X.*"})
	require_NoError(t, err)
	resp, err := nc.Request(fmt.Sprintf(JSApiStreamInfoT, "TEST"), req, 5*time.Second)
	require_NoError(t, err)
	var si StreamInfo
	err = json.Unmarshal(resp.Data, &si)
	require_NoError(t, err)
	if len(si.State.Subjects) != n {
		t.Fatalf("Expected to get %d subject details, got %d", n, len(si.State.Subjects))
	}

	// Now add one more message to check pagination
	_, err = js.Publish("foo", []byte("TOO MUCH"))
	require_NoError(t, err)

	req, err = json.Marshal(&JSApiStreamInfoRequest{ApiPagedRequest: ApiPagedRequest{Offset: n}, SubjectsFilter: nats.AllKeys})
	require_NoError(t, err)
	resp, err = nc.Request(fmt.Sprintf(JSApiStreamInfoT, "TEST"), req, 5*time.Second)
	require_NoError(t, err)
	var sir JSApiStreamInfoResponse
	err = json.Unmarshal(resp.Data, &sir)
	require_NoError(t, err)
	if len(sir.State.Subjects) != 1 {
		t.Fatalf("Expected to get 1 extra subject detail, got %d", len(sir.State.Subjects))
	}
}

func TestNoRaceJetStreamSparseConsumers(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	msg := []byte("ok")

	cases := []struct {
		name    string
		mconfig *nats.StreamConfig
	}{
		{"MemoryStore", &nats.StreamConfig{Name: "TEST", Storage: nats.MemoryStorage, MaxMsgsPerSubject: 25_000_000,
			Subjects: []string{"*"}}},
		{"FileStore", &nats.StreamConfig{Name: "TEST", Storage: nats.FileStorage, MaxMsgsPerSubject: 25_000_000,
			Subjects: []string{"*"}}},
	}
	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			js.DeleteStream("TEST")
			_, err := js.AddStream(c.mconfig)
			require_NoError(t, err)

			// We will purposely place foo msgs near the beginning, then in middle, then at the end.
			for n := 0; n < 2; n++ {
				_, err = js.PublishAsync("foo", msg, nats.StallWait(800*time.Millisecond))
				require_NoError(t, err)

				for i := 0; i < 1_000_000; i++ {
					_, err = js.PublishAsync("bar", msg, nats.StallWait(800*time.Millisecond))
					require_NoError(t, err)
				}
				_, err = js.PublishAsync("foo", msg, nats.StallWait(800*time.Millisecond))
				require_NoError(t, err)
			}
			select {
			case <-js.PublishAsyncComplete():
			case <-time.After(5 * time.Second):
				t.Fatalf("Did not receive completion signal")
			}

			// Now create a consumer on foo.
			ci, err := js.AddConsumer("TEST", &nats.ConsumerConfig{DeliverSubject: "x.x", FilterSubject: "foo", AckPolicy: nats.AckNonePolicy})
			require_NoError(t, err)

			done, received := make(chan bool), uint64(0)

			cb := func(m *nats.Msg) {
				received++
				if received >= ci.NumPending {
					done <- true
				}
			}

			sub, err := nc.Subscribe("x.x", cb)
			require_NoError(t, err)
			defer sub.Unsubscribe()
			start := time.Now()
			var elapsed time.Duration

			select {
			case <-done:
				elapsed = time.Since(start)
			case <-time.After(10 * time.Second):
				t.Fatal("Did not receive all messages for all consumers in time")
			}

			if elapsed > 500*time.Millisecond {
				t.Fatalf("Getting all messages took longer than expected: %v", elapsed)
			}
		})
	}
}

func TestNoRaceJetStreamConsumerFilterPerfDegradation(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, _ := jsClientConnect(t, s)
	defer nc.Close()

	js, err := nc.JetStream(nats.PublishAsyncMaxPending(256))
	require_NoError(t, err)

	_, err = js.AddStream(&nats.StreamConfig{
		Name:     "test",
		Subjects: []string{"test.*.subj"},
		Replicas: 1,
	})
	require_NoError(t, err)

	toSend := 50_000
	count := 0
	ch := make(chan struct{}, 6)
	_, err = js.Subscribe("test.*.subj", func(m *nats.Msg) {
		m.Ack()
		if count++; count == toSend {
			ch <- struct{}{}
		}
	}, nats.DeliverNew(), nats.ManualAck())
	require_NoError(t, err)

	msg := make([]byte, 1024)
	sent := int32(0)
	send := func() {
		defer func() { ch <- struct{}{} }()
		for i := 0; i < toSend/5; i++ {
			msgID := atomic.AddInt32(&sent, 1)
			_, err := js.Publish(fmt.Sprintf("test.%d.subj", msgID), msg)
			if err != nil {
				t.Error(err)
				return
			}
		}
	}
	for i := 0; i < 5; i++ {
		go send()
	}
	timeout := time.NewTimer(10 * time.Second)
	for i := 0; i < 6; i++ {
		select {
		case <-ch:
		case <-timeout.C:
			t.Fatal("Took too long")
		}
	}
}

func TestNoRaceJetStreamFileStoreKeyFileCleanup(t *testing.T) {
	storeDir := t.TempDir()

	prf := func(context []byte) ([]byte, error) {
		h := hmac.New(sha256.New, []byte("dlc22"))
		if _, err := h.Write(context); err != nil {
			return nil, err
		}
		return h.Sum(nil), nil
	}

	fs, err := newFileStoreWithCreated(
		FileStoreConfig{StoreDir: storeDir, BlockSize: 1024 * 1024},
		StreamConfig{Name: "TEST", Storage: FileStorage},
		time.Now(),
		prf, nil)
	require_NoError(t, err)
	defer fs.Stop()

	n, msg := 10_000, []byte(strings.Repeat("Z", 1024))
	for i := 0; i < n; i++ {
		_, _, err := fs.StoreMsg(fmt.Sprintf("X.%d", i), nil, msg)
		require_NoError(t, err)
	}

	var seqs []uint64
	for i := 1; i <= n; i++ {
		seqs = append(seqs, uint64(i))
	}
	// Randomly delete msgs, make sure we cleanup as we empty the message blocks.
	rand.Shuffle(len(seqs), func(i, j int) { seqs[i], seqs[j] = seqs[j], seqs[i] })

	for _, seq := range seqs {
		_, err := fs.RemoveMsg(seq)
		require_NoError(t, err)
	}

	// We will have cleanup the main .blk and .idx sans the lmb, but we should not have any *.fss files.
	kms, err := filepath.Glob(filepath.Join(storeDir, msgDir, keyScanAll))
	require_NoError(t, err)

	if len(kms) > 1 {
		t.Fatalf("Expected to find only 1 key file, found %d", len(kms))
	}
}

func TestNoRaceJetStreamMsgIdPerfDuringCatchup(t *testing.T) {
	// Uncomment to run. Needs to be on a bigger machine. Do not want as part of Travis tests atm.
	skip(t)

	c := createJetStreamClusterExplicit(t, "JSC", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.serverByName("S-1"))
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Replicas: 3,
	})
	require_NoError(t, err)

	// This will be the one we restart.
	sl := c.streamLeader("$G", "TEST")
	// Now move leader.
	_, err = nc.Request(fmt.Sprintf(JSApiStreamLeaderStepDownT, "TEST"), nil, time.Second)
	require_NoError(t, err)
	c.waitOnStreamLeader("$G", "TEST")

	// Connect to new leader.
	nc, _ = jsClientConnect(t, c.streamLeader("$G", "TEST"))
	defer nc.Close()

	js, err = nc.JetStream(nats.PublishAsyncMaxPending(1024))
	require_NoError(t, err)

	n, ss, sr := 1_000_000, 250_000, 800_000
	m := nats.NewMsg("TEST")
	m.Data = []byte(strings.Repeat("Z", 2048))

	// Target rate 10k msgs/sec
	start := time.Now()

	for i := 0; i < n; i++ {
		m.Header.Set(JSMsgId, strconv.Itoa(i))
		_, err := js.PublishMsgAsync(m)
		require_NoError(t, err)
		//time.Sleep(42 * time.Microsecond)
		if i == ss {
			fmt.Printf("SD")
			sl.Shutdown()
		} else if i == sr {
			nc.Flush()
			select {
			case <-js.PublishAsyncComplete():
			case <-time.After(10 * time.Second):
			}
			fmt.Printf("RS")
			sl = c.restartServer(sl)
		}
		if i%10_000 == 0 {
			fmt.Print("#")
		}
	}
	fmt.Println()

	// Wait to receive all messages.
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(20 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	tt := time.Since(start)
	si, err := js.StreamInfo("TEST")
	require_NoError(t, err)

	fmt.Printf("Took %v to send %d msgs\n", tt, n)
	fmt.Printf("%.0f msgs/s\n", float64(n)/tt.Seconds())
	fmt.Printf("%.0f mb/s\n\n", float64(si.State.Bytes/(1024*1024))/tt.Seconds())

	c.waitOnStreamCurrent(sl, "$G", "TEST")
	for _, s := range c.servers {
		mset, _ := s.GlobalAccount().lookupStream("TEST")
		if state := mset.store.State(); state.Msgs != uint64(n) {
			t.Fatalf("Expected server %v to have correct number of msgs %d but got %d", s, n, state.Msgs)
		}
	}
}

func TestNoRaceJetStreamRebuildDeDupeAndMemoryPerf(t *testing.T) {
	skip(t)

	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{Name: "DD"})
	require_NoError(t, err)

	m := nats.NewMsg("DD")
	m.Data = []byte(strings.Repeat("Z", 2048))

	start := time.Now()

	n := 1_000_000
	for i := 0; i < n; i++ {
		m.Header.Set(JSMsgId, strconv.Itoa(i))
		_, err := js.PublishMsgAsync(m)
		require_NoError(t, err)
	}

	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(20 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	tt := time.Since(start)
	si, err := js.StreamInfo("DD")
	require_NoError(t, err)

	fmt.Printf("Took %v to send %d msgs\n", tt, n)
	fmt.Printf("%.0f msgs/s\n", float64(n)/tt.Seconds())
	fmt.Printf("%.0f mb/s\n\n", float64(si.State.Bytes/(1024*1024))/tt.Seconds())

	v, _ := s.Varz(nil)
	fmt.Printf("Memory AFTER SEND: %v\n", friendlyBytes(v.Mem))

	mset, err := s.GlobalAccount().lookupStream("DD")
	require_NoError(t, err)

	mset.mu.Lock()
	mset.ddloaded = false
	start = time.Now()
	mset.rebuildDedupe()
	fmt.Printf("TOOK %v to rebuild dd\n", time.Since(start))
	mset.mu.Unlock()

	v, _ = s.Varz(nil)
	fmt.Printf("Memory: %v\n", friendlyBytes(v.Mem))

	// Now do an ephemeral consumer and whip through every message. Doing same calculations.
	start = time.Now()
	received, done := 0, make(chan bool)
	sub, err := js.Subscribe("DD", func(m *nats.Msg) {
		received++
		if received >= n {
			done <- true
		}
	}, nats.OrderedConsumer())
	require_NoError(t, err)

	select {
	case <-done:
	case <-time.After(10 * time.Second):
		if s.NumSlowConsumers() > 0 {
			t.Fatalf("Did not receive all large messages due to slow consumer status: %d of %d", received, n)
		}
		t.Fatalf("Failed to receive all large messages: %d of %d\n", received, n)
	}

	fmt.Printf("TOOK %v to receive all %d msgs\n", time.Since(start), n)
	sub.Unsubscribe()

	v, _ = s.Varz(nil)
	fmt.Printf("Memory: %v\n", friendlyBytes(v.Mem))
}

func TestNoRaceJetStreamMemoryUsageOnLimitedStreamWithMirror(t *testing.T) {
	skip(t)

	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{Name: "DD", Subjects: []string{"ORDERS.*"}, MaxMsgs: 10_000})
	require_NoError(t, err)

	_, err = js.AddStream(&nats.StreamConfig{
		Name:    "M",
		Mirror:  &nats.StreamSource{Name: "DD"},
		MaxMsgs: 10_000,
	})
	require_NoError(t, err)

	m := nats.NewMsg("ORDERS.0")
	m.Data = []byte(strings.Repeat("Z", 2048))

	start := time.Now()

	n := 1_000_000
	for i := 0; i < n; i++ {
		m.Subject = fmt.Sprintf("ORDERS.%d", i)
		m.Header.Set(JSMsgId, strconv.Itoa(i))
		_, err := js.PublishMsgAsync(m)
		require_NoError(t, err)
	}

	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(20 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	tt := time.Since(start)
	si, err := js.StreamInfo("DD")
	require_NoError(t, err)

	fmt.Printf("Took %v to send %d msgs\n", tt, n)
	fmt.Printf("%.0f msgs/s\n", float64(n)/tt.Seconds())
	fmt.Printf("%.0f mb/s\n\n", float64(si.State.Bytes/(1024*1024))/tt.Seconds())

	v, _ := s.Varz(nil)
	fmt.Printf("Memory AFTER SEND: %v\n", friendlyBytes(v.Mem))
}

func TestNoRaceJetStreamOrderedConsumerLongRTTPerformance(t *testing.T) {
	skip(t)

	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, _ := jsClientConnect(t, s)
	defer nc.Close()

	js, err := nc.JetStream(nats.PublishAsyncMaxPending(1000))
	require_NoError(t, err)

	_, err = js.AddStream(&nats.StreamConfig{Name: "OCP"})
	require_NoError(t, err)

	n, msg := 100_000, []byte(strings.Repeat("D", 30_000))

	for i := 0; i < n; i++ {
		_, err := js.PublishAsync("OCP", msg)
		require_NoError(t, err)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	// Approximately 3GB
	si, err := js.StreamInfo("OCP")
	require_NoError(t, err)

	start := time.Now()
	received, done := 0, make(chan bool)
	sub, err := js.Subscribe("OCP", func(m *nats.Msg) {
		received++
		if received >= n {
			done <- true
		}
	}, nats.OrderedConsumer())
	require_NoError(t, err)
	defer sub.Unsubscribe()

	// Wait to receive all messages.
	select {
	case <-done:
	case <-time.After(30 * time.Second):
		t.Fatalf("Did not receive all of our messages")
	}

	tt := time.Since(start)
	fmt.Printf("Took %v to receive %d msgs\n", tt, n)
	fmt.Printf("%.0f msgs/s\n", float64(n)/tt.Seconds())
	fmt.Printf("%.0f mb/s\n\n", float64(si.State.Bytes/(1024*1024))/tt.Seconds())

	sub.Unsubscribe()

	rtt := 10 * time.Millisecond
	bw := 10 * 1024 * 1024 * 1024
	proxy := newNetProxy(rtt, bw, bw, s.ClientURL())
	defer proxy.stop()

	nc, err = nats.Connect(proxy.clientURL())
	require_NoError(t, err)
	defer nc.Close()
	js, err = nc.JetStream()
	require_NoError(t, err)

	start, received = time.Now(), 0
	sub, err = js.Subscribe("OCP", func(m *nats.Msg) {
		received++
		if received >= n {
			done <- true
		}
	}, nats.OrderedConsumer())
	require_NoError(t, err)
	defer sub.Unsubscribe()

	// Wait to receive all messages.
	select {
	case <-done:
	case <-time.After(60 * time.Second):
		t.Fatalf("Did not receive all of our messages")
	}

	tt = time.Since(start)
	fmt.Printf("Proxy RTT: %v, UP: %d, DOWN: %d\n", rtt, bw, bw)
	fmt.Printf("Took %v to receive %d msgs\n", tt, n)
	fmt.Printf("%.0f msgs/s\n", float64(n)/tt.Seconds())
	fmt.Printf("%.0f mb/s\n\n", float64(si.State.Bytes/(1024*1024))/tt.Seconds())
}

var jsClusterStallCatchupTempl = `
	listen: 127.0.0.1:-1
	server_name: %s
	jetstream: {max_mem_store: 256MB, max_file_store: 32GB, store_dir: '%s'}

	leaf {
		listen: 127.0.0.1:-1
	}

	cluster {
		name: %s
		listen: 127.0.0.1:%d
		routes = [%s]
	}

	# For access to system account.
	accounts { $SYS { users = [ { user: "admin", pass: "s3cr3t!" } ] } }
`

// Test our global stall gate for outstanding catchup bytes.
func TestNoRaceJetStreamClusterCatchupStallGate(t *testing.T) {
	skip(t)

	c := createJetStreamClusterWithTemplate(t, jsClusterStallCatchupTempl, "GSG", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	// ~100k per message.
	msg := []byte(strings.Repeat("A", 99_960))

	// Create 200 streams with 100MB.
	// Each server has ~2GB
	var wg sync.WaitGroup
	for i := 0; i < 20; i++ {
		wg.Add(1)
		go func(x int) {
			defer wg.Done()
			for n := 1; n <= 10; n++ {
				sn := fmt.Sprintf("S-%d", n+x)
				_, err := js.AddStream(&nats.StreamConfig{
					Name:     sn,
					Replicas: 3,
				})
				require_NoError(t, err)
				for i := 0; i < 100; i++ {
					_, err := js.Publish(sn, msg)
					require_NoError(t, err)
				}
			}
		}(i * 20)
	}
	wg.Wait()

	info, err := js.AccountInfo()
	require_NoError(t, err)
	require_True(t, info.Streams == 200)

	runtime.GC()
	debug.FreeOSMemory()

	// Now bring a server down and wipe its storage.
	s := c.servers[0]
	vz, err := s.Varz(nil)
	require_NoError(t, err)
	fmt.Printf("MEM BEFORE is %v\n", friendlyBytes(vz.Mem))

	sd := s.JetStreamConfig().StoreDir
	s.Shutdown()
	removeDir(t, sd)
	s = c.restartServer(s)

	c.waitOnServerHealthz(s)

	runtime.GC()
	debug.FreeOSMemory()

	vz, err = s.Varz(nil)
	require_NoError(t, err)
	fmt.Printf("MEM AFTER is %v\n", friendlyBytes(vz.Mem))
}

func TestNoRaceJetStreamClusterCatchupBailMidway(t *testing.T) {
	skip(t)

	c := createJetStreamClusterWithTemplate(t, jsClusterStallCatchupTempl, "GSG", 3)
	defer c.shutdown()

	ml := c.leader()
	nc, js := jsClientConnect(t, ml)
	defer nc.Close()

	msg := []byte(strings.Repeat("A", 480))

	for i := 0; i < maxConcurrentSyncRequests*2; i++ {
		sn := fmt.Sprintf("CUP-%d", i+1)
		_, err := js.AddStream(&nats.StreamConfig{
			Name:     sn,
			Replicas: 3,
		})
		require_NoError(t, err)

		for i := 0; i < 10_000; i++ {
			_, err := js.PublishAsync(sn, msg)
			require_NoError(t, err)
		}
		select {
		case <-js.PublishAsyncComplete():
		case <-time.After(10 * time.Second):
			t.Fatalf("Did not receive completion signal")
		}
	}

	jsz, _ := ml.Jsz(nil)
	expectedMsgs := jsz.Messages

	// Now select a server and shut it down, removing the storage directory.
	s := c.randomNonLeader()
	sd := s.JetStreamConfig().StoreDir
	s.Shutdown()
	removeDir(t, sd)

	// Now restart the server.
	s = c.restartServer(s)

	// We want to force the follower to bail before the catchup through the
	// upper level catchup logic completes.
	checkFor(t, 5*time.Second, 10*time.Millisecond, func() error {
		jsz, _ := s.Jsz(nil)
		if jsz.Messages > expectedMsgs/2 {
			s.Shutdown()
			return nil
		}
		return fmt.Errorf("Not enough yet")
	})

	// Now restart the server.
	s = c.restartServer(s)

	checkFor(t, 5*time.Second, 500*time.Millisecond, func() error {
		jsz, _ := s.Jsz(nil)
		if jsz.Messages == expectedMsgs {
			return nil
		}
		return fmt.Errorf("Not enough yet")
	})
}

func TestNoRaceJetStreamAccountLimitsAndRestart(t *testing.T) {
	c := createJetStreamClusterWithTemplate(t, jsClusterAccountLimitsTempl, "A3S", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	if _, err := js.AddStream(&nats.StreamConfig{Name: "TEST", Replicas: 3}); err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}

	for i := 0; i < 20_000; i++ {
		if _, err := js.Publish("TEST", []byte("A")); err != nil {
			break
		}
		if i == 5_000 {
			snl := c.randomNonStreamLeader("$JS", "TEST")
			snl.Shutdown()
		}
	}

	c.stopAll()
	c.restartAll()
	c.waitOnLeader()
	c.waitOnStreamLeader("$JS", "TEST")

	for _, cs := range c.servers {
		c.waitOnStreamCurrent(cs, "$JS", "TEST")
	}
}

func TestNoRaceJetStreamPullConsumersAndInteriorDeletes(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "ID", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "foo",
		Replicas:  3,
		MaxMsgs:   50000,
		Retention: nats.InterestPolicy,
	})
	require_NoError(t, err)

	c.waitOnStreamLeader(globalAccountName, "foo")

	_, err = js.AddConsumer("foo", &nats.ConsumerConfig{
		Durable:       "foo",
		FilterSubject: "foo",
		MaxAckPending: 20000,
		AckWait:       time.Minute,
		AckPolicy:     nats.AckExplicitPolicy,
	})
	require_NoError(t, err)

	c.waitOnConsumerLeader(globalAccountName, "foo", "foo")

	rcv := int32(0)
	prods := 5
	cons := 5
	wg := sync.WaitGroup{}
	wg.Add(prods + cons)
	toSend := 100000

	for i := 0; i < cons; i++ {
		go func() {
			defer wg.Done()

			sub, err := js.PullSubscribe("foo", "foo")
			if err != nil {
				return
			}
			for {
				msgs, err := sub.Fetch(200, nats.MaxWait(250*time.Millisecond))
				if err != nil {
					if n := int(atomic.LoadInt32(&rcv)); n >= toSend {
						return
					}
					continue
				}
				for _, m := range msgs {
					m.Ack()
					atomic.AddInt32(&rcv, 1)
				}
			}
		}()
	}

	for i := 0; i < prods; i++ {
		go func() {
			defer wg.Done()

			for i := 0; i < toSend/prods; i++ {
				js.Publish("foo", []byte("hello"))
			}
		}()
	}

	time.Sleep(time.Second)
	resp, err := nc.Request(fmt.Sprintf(JSApiConsumerLeaderStepDownT, "foo", "foo"), nil, time.Second)
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	var cdResp JSApiConsumerLeaderStepDownResponse
	if err := json.Unmarshal(resp.Data, &cdResp); err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	if cdResp.Error != nil {
		t.Fatalf("Unexpected error: %+v", cdResp.Error)
	}
	ch := make(chan struct{})
	go func() {
		wg.Wait()
		close(ch)
	}()
	select {
	case <-ch:
		// OK
	case <-time.After(30 * time.Second):
		t.Fatalf("Consumers took too long to consumer all messages")
	}
}

func TestNoRaceJetStreamClusterInterestPullConsumerStreamLimitBug(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "JSC", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	limit := uint64(1000)

	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "TEST",
		Subjects:  []string{"foo"},
		Retention: nats.InterestPolicy,
		MaxMsgs:   int64(limit),
		Replicas:  3,
	})
	require_NoError(t, err)

	_, err = js.AddConsumer("TEST", &nats.ConsumerConfig{Durable: "dur", AckPolicy: nats.AckExplicitPolicy})
	require_NoError(t, err)

	qch := make(chan bool)
	var wg sync.WaitGroup

	// Publisher
	wg.Add(1)
	go func() {
		defer wg.Done()
		for {
			pt := time.NewTimer(time.Duration(rand.Intn(2)) * time.Millisecond)
			select {
			case <-pt.C:
				_, err := js.Publish("foo", []byte("BUG!"))
				require_NoError(t, err)
			case <-qch:
				pt.Stop()
				return
			}
		}
	}()

	time.Sleep(time.Second)

	// Pull Consumers
	wg.Add(100)
	for i := 0; i < 100; i++ {
		go func() {
			defer wg.Done()
			nc := natsConnect(t, c.randomServer().ClientURL())
			defer nc.Close()

			js, err := nc.JetStream(nats.MaxWait(time.Second))
			require_NoError(t, err)

			var sub *nats.Subscription
			for j := 0; j < 5; j++ {
				sub, err = js.PullSubscribe("foo", "dur")
				if err == nil {
					break
				}
			}
			require_NoError(t, err)

			for {
				pt := time.NewTimer(time.Duration(rand.Intn(300)) * time.Millisecond)
				select {
				case <-pt.C:
					msgs, err := sub.Fetch(1)
					if err != nil {
						t.Logf("Got a Fetch error: %v", err)
						return
					}
					if len(msgs) > 0 {
						go func() {
							ackDelay := time.Duration(rand.Intn(375)+15) * time.Millisecond
							m := msgs[0]
							time.AfterFunc(ackDelay, func() { m.AckSync() })
						}()
					}
				case <-qch:
					return
				}
			}
		}()
	}

	// Make sure we have hit the limit for the number of messages we expected.
	checkFor(t, 20*time.Second, 500*time.Millisecond, func() error {
		si, err := js.StreamInfo("TEST")
		require_NoError(t, err)
		if si.State.Msgs < limit {
			return fmt.Errorf("Not hit limit yet")
		}
		return nil
	})

	close(qch)
	wg.Wait()

	checkFor(t, 20*time.Second, 500*time.Millisecond, func() error {
		si, err := js.StreamInfo("TEST")
		require_NoError(t, err)
		ci, err := js.ConsumerInfo("TEST", "dur")
		require_NoError(t, err)

		np := ci.NumPending + uint64(ci.NumAckPending)
		if np != si.State.Msgs {
			return fmt.Errorf("Expected NumPending to be %d got %d", si.State.Msgs-uint64(ci.NumAckPending), ci.NumPending)
		}
		return nil
	})
}

// Test that all peers have the direct access subs that participate in a queue group,
// but only when they are current and ready. So we will start with R1, add in messages
// then scale up while also still adding messages.
func TestNoRaceJetStreamClusterDirectAccessAllPeersSubs(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "JSC", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	// Start as R1
	cfg := &StreamConfig{
		Name:        "TEST",
		Subjects:    []string{"kv.>"},
		MaxMsgsPer:  10,
		AllowDirect: true,
		Replicas:    1,
		Storage:     FileStorage,
	}
	addStream(t, nc, cfg)

	// Seed with enough messages to start then we will scale up while still adding more messages.
	num, msg := 1000, bytes.Repeat([]byte("XYZ"), 64)
	for i := 0; i < num; i++ {
		js.PublishAsync(fmt.Sprintf("kv.%d", i), msg)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	getSubj := fmt.Sprintf(JSDirectMsgGetT, "TEST")
	getMsg := func(key string) *nats.Msg {
		t.Helper()
		req := []byte(fmt.Sprintf(`{"last_by_subj":%q}`, key))
		m, err := nc.Request(getSubj, req, time.Second)
		require_NoError(t, err)
		require_True(t, m.Header.Get(JSSubject) == key)
		return m
	}

	// Just make sure we can succeed here.
	getMsg("kv.22")

	// Now crank up a go routine to continue sending more messages.
	qch := make(chan bool)
	var wg sync.WaitGroup

	for i := 0; i < 5; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			nc, js := jsClientConnect(t, c.randomServer())
			defer nc.Close()
			for {
				select {
				case <-qch:
					select {
					case <-js.PublishAsyncComplete():
					case <-time.After(10 * time.Second):
					}
					return
				default:
					// Send as fast as we can.
					js.Publish(fmt.Sprintf("kv.%d", rand.Intn(1000)), msg)
				}
			}
		}()
	}

	time.Sleep(200 * time.Millisecond)

	// Now let's scale up to an R3.
	cfg.Replicas = 3
	updateStream(t, nc, cfg)

	// Wait for the stream to register the new replicas and have a leader.
	checkFor(t, 20*time.Second, 500*time.Millisecond, func() error {
		si, err := js.StreamInfo("TEST")
		if err != nil {
			return err
		}
		if si.Cluster == nil {
			return fmt.Errorf("No cluster yet")
		}
		if si.Cluster.Leader == _EMPTY_ || len(si.Cluster.Replicas) != 2 {
			return fmt.Errorf("Cluster not ready yet")
		}
		return nil
	})

	close(qch)
	wg.Wait()

	// Just make sure we can succeed here.
	getMsg("kv.22")

	// For each non-leader check that the direct sub fires up.
	// We just test all, the leader will already have a directSub.
	for _, s := range c.servers {
		mset, err := s.GlobalAccount().lookupStream("TEST")
		require_NoError(t, err)
		checkFor(t, 20*time.Second, 500*time.Millisecond, func() error {
			mset.mu.RLock()
			ok := mset.directSub != nil
			mset.mu.RUnlock()
			if ok {
				return nil
			}
			return fmt.Errorf("No directSub yet")
		})
	}

	si, err := js.StreamInfo("TEST")
	require_NoError(t, err)

	if si.State.Msgs == uint64(num) {
		t.Fatalf("Expected to see messages increase, got %d", si.State.Msgs)
	}

	checkFor(t, 10*time.Second, 500*time.Millisecond, func() error {
		// Make sure they are all the same from a state perspective.
		// Leader will have the expected state.
		lmset, err := c.streamLeader("$G", "TEST").GlobalAccount().lookupStream("TEST")
		require_NoError(t, err)
		expected := lmset.state()

		for _, s := range c.servers {
			mset, err := s.GlobalAccount().lookupStream("TEST")
			require_NoError(t, err)
			if state := mset.state(); !reflect.DeepEqual(expected, state) {
				return fmt.Errorf("Expected %+v, got %+v", expected, state)
			}
		}
		return nil
	})

}

func TestNoRaceJetStreamClusterStreamNamesAndInfosMoreThanAPILimit(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	s := c.randomServer()
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	createStream := func(name string) {
		t.Helper()
		if _, err := js.AddStream(&nats.StreamConfig{Name: name}); err != nil {
			t.Fatalf("Unexpected error: %v", err)
		}
	}

	max := JSApiListLimit
	if JSApiNamesLimit > max {
		max = JSApiNamesLimit
	}
	max += 10

	for i := 0; i < max; i++ {
		name := fmt.Sprintf("foo_%d", i)
		createStream(name)
	}

	// Not using the JS API here because we want to make sure that the
	// server returns the proper Total count, but also that it does not
	// send more than when the API limit is in one go.
	check := func(subj string, limit int) {
		t.Helper()

		nreq := JSApiStreamNamesRequest{}
		b, _ := json.Marshal(nreq)

		msg, err := nc.Request(subj, b, 2*time.Second)
		require_NoError(t, err)

		switch subj {
		case JSApiStreams:
			nresp := JSApiStreamNamesResponse{}
			json.Unmarshal(msg.Data, &nresp)
			if n := nresp.ApiPaged.Total; n != max {
				t.Fatalf("Expected total to be %v, got %v", max, n)
			}
			if n := nresp.ApiPaged.Limit; n != limit {
				t.Fatalf("Expected limit to be %v, got %v", limit, n)
			}
			if n := len(nresp.Streams); n != limit {
				t.Fatalf("Expected number of streams to be %v, got %v", limit, n)
			}
		case JSApiStreamList:
			nresp := JSApiStreamListResponse{}
			json.Unmarshal(msg.Data, &nresp)
			if n := nresp.ApiPaged.Total; n != max {
				t.Fatalf("Expected total to be %v, got %v", max, n)
			}
			if n := nresp.ApiPaged.Limit; n != limit {
				t.Fatalf("Expected limit to be %v, got %v", limit, n)
			}
			if n := len(nresp.Streams); n != limit {
				t.Fatalf("Expected number of streams to be %v, got %v", limit, n)
			}
		}
	}

	check(JSApiStreams, JSApiNamesLimit)
	check(JSApiStreamList, JSApiListLimit)
}

func TestNoRaceJetStreamClusterConsumerListPaging(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	s := c.randomNonLeader()
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo"},
		Replicas: 3,
	})
	require_NoError(t, err)
	c.waitOnStreamLeader(globalAccountName, "TEST")

	cfg := &nats.ConsumerConfig{
		Replicas:      1,
		MemoryStorage: true,
		AckPolicy:     nats.AckExplicitPolicy,
	}

	// create 3000 consumers.
	numConsumers := 3000
	for i := 1; i <= numConsumers; i++ {
		cfg.Durable = fmt.Sprintf("d-%.4d", i)
		_, err := js.AddConsumer("TEST", cfg)
		require_NoError(t, err)
	}

	// Test both names and list operations.

	// Names
	reqSubj := fmt.Sprintf(JSApiConsumersT, "TEST")
	grabConsumerNames := func(offset int) []string {
		req := fmt.Sprintf(`{"offset":%d}`, offset)
		respMsg, err := nc.Request(reqSubj, []byte(req), time.Second)
		require_NoError(t, err)
		var resp JSApiConsumerNamesResponse
		err = json.Unmarshal(respMsg.Data, &resp)
		require_NoError(t, err)
		// Sanity check that we are actually paging properly around limits.
		if resp.Limit < len(resp.Consumers) {
			t.Fatalf("Expected total limited to %d but got %d", resp.Limit, len(resp.Consumers))
		}
		if resp.Total != numConsumers {
			t.Fatalf("Invalid total response: expected %d got %d", numConsumers, resp.Total)
		}
		return resp.Consumers
	}

	results := make(map[string]bool)

	for offset := 0; len(results) < numConsumers; {
		consumers := grabConsumerNames(offset)
		offset += len(consumers)
		for _, name := range consumers {
			if results[name] {
				t.Fatalf("Found duplicate %q", name)
			}
			results[name] = true
		}
	}

	// List
	reqSubj = fmt.Sprintf(JSApiConsumerListT, "TEST")
	grabConsumerList := func(offset int) []*ConsumerInfo {
		req := fmt.Sprintf(`{"offset":%d}`, offset)
		respMsg, err := nc.Request(reqSubj, []byte(req), time.Second)
		require_NoError(t, err)
		var resp JSApiConsumerListResponse
		err = json.Unmarshal(respMsg.Data, &resp)
		require_NoError(t, err)
		// Sanity check that we are actually paging properly around limits.
		if resp.Limit < len(resp.Consumers) {
			t.Fatalf("Expected total limited to %d but got %d", resp.Limit, len(resp.Consumers))
		}
		if resp.Total != numConsumers {
			t.Fatalf("Invalid total response: expected %d got %d", numConsumers, resp.Total)
		}
		return resp.Consumers
	}

	results = make(map[string]bool)

	for offset := 0; len(results) < numConsumers; {
		consumers := grabConsumerList(offset)
		offset += len(consumers)
		for _, ci := range consumers {
			name := ci.Config.Durable
			if results[name] {
				t.Fatalf("Found duplicate %q", name)
			}
			results[name] = true
		}
	}

	if len(results) != numConsumers {
		t.Fatalf("Received %d / %d consumers", len(results), numConsumers)
	}
}

func TestNoRaceJetStreamFileStoreLargeKVAccessTiming(t *testing.T) {
	storeDir := t.TempDir()

	blkSize := uint64(4 * 1024)
	// Compensate for slower IO on MacOSX
	if runtime.GOOS == "darwin" {
		blkSize *= 4
	}

	fs, err := newFileStore(
		FileStoreConfig{StoreDir: storeDir, BlockSize: blkSize, CacheExpire: 30 * time.Second},
		StreamConfig{Name: "zzz", Subjects: []string{"KV.STREAM_NAME.*"}, Storage: FileStorage, MaxMsgsPer: 1},
	)
	require_NoError(t, err)
	defer fs.Stop()

	tmpl := "KV.STREAM_NAME.%d"
	nkeys, val := 100_000, bytes.Repeat([]byte("Z"), 1024)

	for i := 1; i <= nkeys; i++ {
		subj := fmt.Sprintf(tmpl, i)
		_, _, err := fs.StoreMsg(subj, nil, val)
		require_NoError(t, err)
	}

	first := fmt.Sprintf(tmpl, 1)
	last := fmt.Sprintf(tmpl, nkeys)

	start := time.Now()
	sm, err := fs.LoadLastMsg(last, nil)
	require_NoError(t, err)
	base := time.Since(start)

	if !bytes.Equal(sm.msg, val) {
		t.Fatalf("Retrieved value did not match")
	}

	start = time.Now()
	_, err = fs.LoadLastMsg(first, nil)
	require_NoError(t, err)
	slow := time.Since(start)

	if base > 100*time.Microsecond || slow > 200*time.Microsecond {
		t.Fatalf("Took too long to look up first key vs last: %v vs %v", base, slow)
	}

	// time first seq lookup for both as well.
	// Base will be first in this case.
	fs.mu.Lock()
	start = time.Now()
	fs.firstSeqForSubj(first)
	base = time.Since(start)
	start = time.Now()
	fs.firstSeqForSubj(last)
	slow = time.Since(start)
	fs.mu.Unlock()

	if base > 100*time.Microsecond || slow > 200*time.Microsecond {
		t.Fatalf("Took too long to look up last key by subject vs first: %v vs %v", base, slow)
	}
}

func TestNoRaceJetStreamKVLock(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.CreateKeyValue(&nats.KeyValueConfig{Bucket: "LOCKS"})
	require_NoError(t, err)

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	var wg sync.WaitGroup
	start := make(chan bool)

	var tracker int64

	for i := 0; i < 100; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()

			nc, js := jsClientConnect(t, s)
			defer nc.Close()
			kv, err := js.KeyValue("LOCKS")
			require_NoError(t, err)

			<-start

			for {
				last, err := kv.Create("MY_LOCK", []byte("Z"))
				if err != nil {
					select {
					case <-time.After(10 * time.Millisecond):
						continue
					case <-ctx.Done():
						return
					}
				}

				if v := atomic.AddInt64(&tracker, 1); v != 1 {
					t.Logf("TRACKER NOT 1 -> %d\n", v)
					cancel()
				}

				time.Sleep(10 * time.Millisecond)
				if v := atomic.AddInt64(&tracker, -1); v != 0 {
					t.Logf("TRACKER NOT 0 AFTER RELEASE -> %d\n", v)
					cancel()
				}

				err = kv.Delete("MY_LOCK", nats.LastRevision(last))
				if err != nil {
					t.Logf("Could not unlock for last %d: %v", last, err)
				}

				if ctx.Err() != nil {
					return
				}
			}
		}()
	}

	close(start)
	wg.Wait()
}

func TestNoRaceJetStreamSuperClusterStreamMoveLongRTT(t *testing.T) {
	// Make C2 far away.
	gwm := gwProxyMap{
		"C2": &gwProxy{
			rtt:  20 * time.Millisecond,
			up:   1 * 1024 * 1024 * 1024, // 1gbit
			down: 1 * 1024 * 1024 * 1024, // 1gbit
		},
	}
	sc := createJetStreamTaggedSuperClusterWithGWProxy(t, gwm)
	defer sc.shutdown()

	nc, js := jsClientConnect(t, sc.randomServer())
	defer nc.Close()

	cfg := &nats.StreamConfig{
		Name:      "TEST",
		Subjects:  []string{"chunk.*"},
		Placement: &nats.Placement{Tags: []string{"cloud:aws", "country:us"}},
		Replicas:  3,
	}

	// Place a stream in C1.
	_, err := js.AddStream(cfg, nats.MaxWait(10*time.Second))
	require_NoError(t, err)

	chunk := bytes.Repeat([]byte("Z"), 1000*1024) // ~1MB
	// 256 MB
	for i := 0; i < 256; i++ {
		subj := fmt.Sprintf("chunk.%d", i)
		js.PublishAsync(subj, chunk)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(10 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	// C2, slow RTT.
	cfg.Placement = &nats.Placement{Tags: []string{"cloud:gcp", "country:uk"}}
	_, err = js.UpdateStream(cfg)
	require_NoError(t, err)

	checkFor(t, 20*time.Second, time.Second, func() error {
		si, err := js.StreamInfo("TEST", nats.MaxWait(time.Second))
		if err != nil {
			return err
		}
		if si.Cluster.Name != "C2" {
			return fmt.Errorf("Wrong cluster: %q", si.Cluster.Name)
		}
		if si.Cluster.Leader == _EMPTY_ {
			return fmt.Errorf("No leader yet")
		} else if !strings.HasPrefix(si.Cluster.Leader, "C2-") {
			return fmt.Errorf("Wrong leader: %q", si.Cluster.Leader)
		}
		// Now we want to see that we shrink back to original.
		if len(si.Cluster.Replicas) != cfg.Replicas-1 {
			return fmt.Errorf("Expected %d replicas, got %d", cfg.Replicas-1, len(si.Cluster.Replicas))
		}
		return nil
	})
}

// https://github.com/nats-io/nats-server/issues/3455
func TestNoRaceJetStreamConcurrentPullConsumerBatch(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "TEST",
		Subjects:  []string{"ORDERS.*"},
		Storage:   nats.MemoryStorage,
		Retention: nats.WorkQueuePolicy,
	})
	require_NoError(t, err)

	toSend := int32(100_000)

	for i := 0; i < 100_000; i++ {
		subj := fmt.Sprintf("ORDERS.%d", i+1)
		js.PublishAsync(subj, []byte("BUY"))
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	_, err = js.AddConsumer("TEST", &nats.ConsumerConfig{
		Durable:       "PROCESSOR",
		AckPolicy:     nats.AckExplicitPolicy,
		MaxAckPending: 5000,
	})
	require_NoError(t, err)

	nc, js = jsClientConnect(t, s)
	defer nc.Close()

	sub1, err := js.PullSubscribe(_EMPTY_, _EMPTY_, nats.Bind("TEST", "PROCESSOR"))
	require_NoError(t, err)

	nc, js = jsClientConnect(t, s)
	defer nc.Close()

	sub2, err := js.PullSubscribe(_EMPTY_, _EMPTY_, nats.Bind("TEST", "PROCESSOR"))
	require_NoError(t, err)

	startCh := make(chan bool)

	var received int32

	wg := sync.WaitGroup{}

	fetchSize := 1000
	fetch := func(sub *nats.Subscription) {
		<-startCh
		defer wg.Done()

		for {
			msgs, err := sub.Fetch(fetchSize, nats.MaxWait(time.Second))
			if atomic.AddInt32(&received, int32(len(msgs))) >= toSend {
				break
			}
			// We should always receive a full batch here if not last competing fetch.
			if err != nil || len(msgs) != fetchSize {
				break
			}
			for _, m := range msgs {
				m.Ack()
			}
		}
	}

	wg.Add(2)

	go fetch(sub1)
	go fetch(sub2)

	close(startCh)

	wg.Wait()
	require_True(t, received == toSend)
}

func TestNoRaceJetStreamManyPullConsumersNeedAckOptimization(t *testing.T) {
	// Uncomment to run. Do not want as part of Travis tests atm.
	// Run with cpu and memory profiling to make sure we have improved.
	skip(t)

	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "ORDERS",
		Subjects:  []string{"ORDERS.*"},
		Storage:   nats.MemoryStorage,
		Retention: nats.InterestPolicy,
	})
	require_NoError(t, err)

	toSend := 100_000
	numConsumers := 500

	// Create 500 consumers
	for i := 1; i <= numConsumers; i++ {
		_, err := js.AddConsumer("ORDERS", &nats.ConsumerConfig{
			Durable:       fmt.Sprintf("ORDERS_%d", i),
			FilterSubject: fmt.Sprintf("ORDERS.%d", i),
			AckPolicy:     nats.AckAllPolicy,
		})
		require_NoError(t, err)
	}

	for i := 1; i <= toSend; i++ {
		subj := fmt.Sprintf("ORDERS.%d", i%numConsumers+1)
		js.PublishAsync(subj, []byte("HELLO"))
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	sub, err := js.PullSubscribe("ORDERS.500", "ORDERS_500")
	require_NoError(t, err)

	fetchSize := toSend / numConsumers
	msgs, err := sub.Fetch(fetchSize, nats.MaxWait(time.Second))
	require_NoError(t, err)

	last := msgs[len(msgs)-1]
	last.AckSync()
}

// https://github.com/nats-io/nats-server/issues/3499
func TestNoRaceJetStreamDeleteConsumerWithInterestStreamAndHighSeqs(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	// Client for API requests.
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "TEST",
		Subjects:  []string{"log.>"},
		Retention: nats.InterestPolicy,
	})
	require_NoError(t, err)

	_, err = js.AddConsumer("TEST", &nats.ConsumerConfig{
		Durable:   "c",
		AckPolicy: nats.AckExplicitPolicy,
	})
	require_NoError(t, err)

	// Set baseline for time to delete so we can see linear increase as sequence numbers increase.
	start := time.Now()
	err = js.DeleteConsumer("TEST", "c")
	require_NoError(t, err)
	elapsed := time.Since(start)

	// Crank up sequence numbers.
	msg := []byte(strings.Repeat("ZZZ", 128))
	for i := 0; i < 5_000_000; i++ {
		nc.Publish("log.Z", msg)
	}
	nc.Flush()

	_, err = js.AddConsumer("TEST", &nats.ConsumerConfig{
		Durable:   "c",
		AckPolicy: nats.AckExplicitPolicy,
	})
	require_NoError(t, err)

	// We have a bug that spins unecessarily through all the sequences from this consumer's
	// ackfloor(0) and the last sequence for the stream. We will detect by looking for the time
	// to delete being 100x more. Should be the same since both times no messages exist in the stream.
	start = time.Now()
	err = js.DeleteConsumer("TEST", "c")
	require_NoError(t, err)

	if e := time.Since(start); e > 100*elapsed {
		t.Fatalf("Consumer delete took too long: %v vs baseline %v", e, elapsed)
	}
}

// Bug when we encode a timestamp that upon decode causes an error which causes server to panic.
// This can happen on consumer redelivery since they adjusted timstamps can be in the future, and result
// in a negative encoding. If that encoding was exactly -1 seconds, would cause decodeConsumerState to fail
// and the server to panic.
func TestNoRaceEncodeConsumerStateBug(t *testing.T) {
	for i := 0; i < 200_000; i++ {
		// Pretend we redelivered and updated the timestamp to reflect the new start time for expiration.
		// The bug will trip when time.Now() rounded to seconds in encode is 1 second below the truncated version
		// of pending.
		pending := Pending{Sequence: 1, Timestamp: time.Now().Add(time.Second).UnixNano()}
		state := ConsumerState{
			Delivered: SequencePair{Consumer: 1, Stream: 1},
			Pending:   map[uint64]*Pending{1: &pending},
		}
		buf := encodeConsumerState(&state)
		_, err := decodeConsumerState(buf)
		require_NoError(t, err)
	}
}

// Performance impact on stream ingress with large number of consumers.
func TestNoRaceJetStreamLargeNumConsumersPerfImpact(t *testing.T) {
	skip(t)

	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	// Client for API requests.
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo"},
	})
	require_NoError(t, err)

	// Baseline with no consumers.
	toSend := 1_000_000
	start := time.Now()
	for i := 0; i < toSend; i++ {
		js.PublishAsync("foo", []byte("OK"))
	}
	<-js.PublishAsyncComplete()
	tt := time.Since(start)
	fmt.Printf("Base time is %v\n", tt)
	fmt.Printf("%.0f msgs/sec\n", float64(toSend)/tt.Seconds())

	err = js.PurgeStream("TEST")
	require_NoError(t, err)

	// Now add in 10 idle consumers.
	for i := 1; i <= 10; i++ {
		_, err := js.AddConsumer("TEST", &nats.ConsumerConfig{
			Durable:   fmt.Sprintf("d-%d", i),
			AckPolicy: nats.AckExplicitPolicy,
		})
		require_NoError(t, err)
	}

	start = time.Now()
	for i := 0; i < toSend; i++ {
		js.PublishAsync("foo", []byte("OK"))
	}
	<-js.PublishAsyncComplete()
	tt = time.Since(start)
	fmt.Printf("\n10 consumers time is %v\n", tt)
	fmt.Printf("%.0f msgs/sec\n", float64(toSend)/tt.Seconds())

	err = js.PurgeStream("TEST")
	require_NoError(t, err)

	// Now add in 90 more idle consumers.
	for i := 11; i <= 100; i++ {
		_, err := js.AddConsumer("TEST", &nats.ConsumerConfig{
			Durable:   fmt.Sprintf("d-%d", i),
			AckPolicy: nats.AckExplicitPolicy,
		})
		require_NoError(t, err)
	}

	start = time.Now()
	for i := 0; i < toSend; i++ {
		js.PublishAsync("foo", []byte("OK"))
	}
	<-js.PublishAsyncComplete()
	tt = time.Since(start)
	fmt.Printf("\n100 consumers time is %v\n", tt)
	fmt.Printf("%.0f msgs/sec\n", float64(toSend)/tt.Seconds())

	err = js.PurgeStream("TEST")
	require_NoError(t, err)

	// Now add in 900 more
	for i := 101; i <= 1000; i++ {
		_, err := js.AddConsumer("TEST", &nats.ConsumerConfig{
			Durable:   fmt.Sprintf("d-%d", i),
			AckPolicy: nats.AckExplicitPolicy,
		})
		require_NoError(t, err)
	}

	start = time.Now()
	for i := 0; i < toSend; i++ {
		js.PublishAsync("foo", []byte("OK"))
	}
	<-js.PublishAsyncComplete()
	tt = time.Since(start)
	fmt.Printf("\n1000 consumers time is %v\n", tt)
	fmt.Printf("%.0f msgs/sec\n", float64(toSend)/tt.Seconds())
}

// Performance impact on large number of consumers but sparse delivery.
func TestNoRaceJetStreamLargeNumConsumersSparseDelivery(t *testing.T) {
	skip(t)

	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	// Client for API requests.
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"ID.*"},
	})
	require_NoError(t, err)

	// Now add in ~10k consumers on different subjects.
	for i := 3; i <= 10_000; i++ {
		_, err := js.AddConsumer("TEST", &nats.ConsumerConfig{
			Durable:       fmt.Sprintf("d-%d", i),
			FilterSubject: fmt.Sprintf("ID.%d", i),
			AckPolicy:     nats.AckNonePolicy,
		})
		require_NoError(t, err)
	}

	toSend := 100_000

	// Bind a consumer to ID.2.
	var received int
	done := make(chan bool)

	nc, js = jsClientConnect(t, s)
	defer nc.Close()

	mh := func(m *nats.Msg) {
		received++
		if received >= toSend {
			close(done)
		}
	}
	_, err = js.Subscribe("ID.2", mh)
	require_NoError(t, err)

	last := make(chan bool)
	_, err = js.Subscribe("ID.1", func(_ *nats.Msg) { close(last) })
	require_NoError(t, err)

	nc, _ = jsClientConnect(t, s)
	defer nc.Close()
	js, err = nc.JetStream(nats.PublishAsyncMaxPending(8 * 1024))
	require_NoError(t, err)

	start := time.Now()
	for i := 0; i < toSend; i++ {
		js.PublishAsync("ID.2", []byte("ok"))
	}
	// Check latency for this one message.
	// This will show the issue better than throughput which can bypass signal processing.
	js.PublishAsync("ID.1", []byte("ok"))

	select {
	case <-done:
		break
	case <-time.After(10 * time.Second):
		t.Fatalf("Failed to receive all messages: %d of %d\n", received, toSend)
	}

	tt := time.Since(start)
	fmt.Printf("Took %v to receive %d msgs\n", tt, toSend)
	fmt.Printf("%.0f msgs/s\n", float64(toSend)/tt.Seconds())

	select {
	case <-last:
		break
	case <-time.After(30 * time.Second):
		t.Fatalf("Failed to receive last message\n")
	}
	lt := time.Since(start)

	fmt.Printf("Took %v to receive last msg\n", lt)
}

func TestNoRaceJetStreamEndToEndLatency(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	// Client for API requests.
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo"},
	})
	require_NoError(t, err)

	nc, js = jsClientConnect(t, s)
	defer nc.Close()

	var sent time.Time
	var max time.Duration
	next := make(chan struct{})

	mh := func(m *nats.Msg) {
		received := time.Now()
		tt := received.Sub(sent)
		if max == 0 || tt > max {
			max = tt
		}
		next <- struct{}{}
	}
	sub, err := js.Subscribe("foo", mh)
	require_NoError(t, err)

	nc, js = jsClientConnect(t, s)
	defer nc.Close()

	toSend := 50_000
	for i := 0; i < toSend; i++ {
		sent = time.Now()
		js.Publish("foo", []byte("ok"))
		<-next
	}
	sub.Unsubscribe()

	if max > 250*time.Millisecond {
		t.Fatalf("Expected max latency to be < 250ms, got %v", max)
	}
}

func TestNoRaceJetStreamClusterEnsureWALCompact(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo"},
		Replicas: 3,
	})
	require_NoError(t, err)

	_, err = js.AddConsumer("TEST", &nats.ConsumerConfig{
		Durable:        "dlc",
		DeliverSubject: "zz",
		Replicas:       3,
	})
	require_NoError(t, err)

	// Force snapshot on stream leader.
	sl := c.streamLeader(globalAccountName, "TEST")
	mset, err := sl.GlobalAccount().lookupStream("TEST")
	require_NoError(t, err)
	node := mset.raftNode()
	require_True(t, node != nil)

	err = node.InstallSnapshot(mset.stateSnapshot())
	require_NoError(t, err)

	// Now publish more than should be needed to cause an additional snapshot.
	ns := 75_000
	for i := 0; i <= ns; i++ {
		_, err := js.Publish("foo", []byte("bar"))
		require_NoError(t, err)
	}

	// Grab progress and use that to look into WAL entries.
	_, _, applied := node.Progress()
	// If ne == ns that means snapshots and compacts were not happening when
	// they should have been.
	if ne, _ := node.Applied(applied); ne >= uint64(ns) {
		t.Fatalf("Did not snapshot and compact the raft WAL, entries == %d", ne)
	}

	// Now check consumer.
	// Force snapshot on consumerleader.
	cl := c.consumerLeader(globalAccountName, "TEST", "dlc")
	mset, err = cl.GlobalAccount().lookupStream("TEST")
	require_NoError(t, err)
	o := mset.lookupConsumer("dlc")
	require_True(t, o != nil)

	node = o.raftNode()
	require_True(t, node != nil)

	snap, err := o.store.EncodedState()
	require_NoError(t, err)
	err = node.InstallSnapshot(snap)
	require_NoError(t, err)

	received, done := 0, make(chan bool, 1)

	nc.Subscribe("zz", func(m *nats.Msg) {
		received++
		if received >= ns {
			select {
			case done <- true:
			default:
			}
		}
		m.Ack()
	})

	select {
	case <-done:
		return
	case <-time.After(10 * time.Second):
		t.Fatalf("Did not received all %d msgs, only %d", ns, received)
	}

	// Do same trick and check that WAL was compacted.
	// Grab progress and use that to look into WAL entries.
	_, _, applied = node.Progress()
	// If ne == ns that means snapshots and compacts were not happening when
	// they should have been.
	if ne, _ := node.Applied(applied); ne >= uint64(ns) {
		t.Fatalf("Did not snapshot and compact the raft WAL, entries == %d", ne)
	}
}

func TestNoRaceFileStoreStreamMaxAgePerformance(t *testing.T) {
	// Uncomment to run.
	skip(t)

	storeDir := t.TempDir()
	maxAge := 5 * time.Second

	fs, err := newFileStore(
		FileStoreConfig{StoreDir: storeDir},
		StreamConfig{Name: "MA",
			Subjects: []string{"foo.*"},
			MaxAge:   maxAge,
			Storage:  FileStorage},
	)
	require_NoError(t, err)
	defer fs.Stop()

	// Simulate a callback similar to consumers decrementing.
	var mu sync.RWMutex
	var pending int64

	fs.RegisterStorageUpdates(func(md, bd int64, seq uint64, subj string) {
		mu.Lock()
		defer mu.Unlock()
		pending += md
	})

	start, num, subj := time.Now(), 0, "foo.foo"

	timeout := start.Add(maxAge)
	for time.Now().Before(timeout) {
		// We will store in blocks of 100.
		for i := 0; i < 100; i++ {
			_, _, err := fs.StoreMsg(subj, nil, []byte("Hello World"))
			require_NoError(t, err)
			num++
		}
	}
	elapsed := time.Since(start)
	fmt.Printf("Took %v to store %d\n", elapsed, num)
	fmt.Printf("%.0f msgs/sec\n", float64(num)/elapsed.Seconds())

	// Now keep running for 2x longer knowing we are expiring messages in the background.
	// We want to see the effect on performance.

	start = time.Now()
	timeout = start.Add(maxAge * 2)

	for time.Now().Before(timeout) {
		// We will store in blocks of 100.
		for i := 0; i < 100; i++ {
			_, _, err := fs.StoreMsg(subj, nil, []byte("Hello World"))
			require_NoError(t, err)
			num++
		}
	}
	elapsed = time.Since(start)
	fmt.Printf("Took %v to store %d\n", elapsed, num)
	fmt.Printf("%.0f msgs/sec\n", float64(num)/elapsed.Seconds())
}

// SequenceSet memory tests vs dmaps.
func TestNoRaceSeqSetSizeComparison(t *testing.T) {
	// Create 5M random entries (dupes possible but ok for this test) out of 8M range.
	num := 5_000_000
	max := 7_000_000

	seqs := make([]uint64, 0, num)
	for i := 0; i < num; i++ {
		n := uint64(rand.Int63n(int64(max + 1)))
		seqs = append(seqs, n)
	}

	runtime.GC()
	// Disable to get stable results.
	gcp := debug.SetGCPercent(-1)
	defer debug.SetGCPercent(gcp)

	mem := runtime.MemStats{}
	runtime.ReadMemStats(&mem)
	inUseBefore := mem.HeapInuse

	dmap := make(map[uint64]struct{}, num)
	for _, n := range seqs {
		dmap[n] = struct{}{}
	}
	runtime.ReadMemStats(&mem)
	dmapUse := mem.HeapInuse - inUseBefore
	inUseBefore = mem.HeapInuse

	// Now do SequenceSet on same dataset.
	var sset avl.SequenceSet
	for _, n := range seqs {
		sset.Insert(n)
	}

	runtime.ReadMemStats(&mem)
	seqSetUse := mem.HeapInuse - inUseBefore

	if seqSetUse > 2*1024*1024 {
		t.Fatalf("Expected SequenceSet size to be < 2M, got %v", friendlyBytes(int64(seqSetUse)))
	}
	if seqSetUse*50 > dmapUse {
		t.Fatalf("Expected SequenceSet to be at least 50x better then dmap approach: %v vs %v",
			friendlyBytes(int64(seqSetUse)),
			friendlyBytes(int64(dmapUse)),
		)
	}
}

// FilteredState for ">" with large interior deletes was very slow.
func TestNoRaceFileStoreFilteredStateWithLargeDeletes(t *testing.T) {
	storeDir := t.TempDir()

	fs, err := newFileStore(
		FileStoreConfig{StoreDir: storeDir, BlockSize: 4096},
		StreamConfig{Name: "zzz", Subjects: []string{"foo"}, Storage: FileStorage},
	)
	require_NoError(t, err)
	defer fs.Stop()

	subj, msg := "foo", []byte("Hello World")

	toStore := 500_000
	for i := 0; i < toStore; i++ {
		_, _, err := fs.StoreMsg(subj, nil, msg)
		require_NoError(t, err)
	}

	// Now delete every other one.
	for seq := 2; seq <= toStore; seq += 2 {
		_, err := fs.RemoveMsg(uint64(seq))
		require_NoError(t, err)
	}

	runtime.GC()
	// Disable to get stable results.
	gcp := debug.SetGCPercent(-1)
	defer debug.SetGCPercent(gcp)

	start := time.Now()
	fss := fs.FilteredState(1, _EMPTY_)
	elapsed := time.Since(start)

	require_True(t, fss.Msgs == uint64(toStore/2))
	require_True(t, elapsed < 500*time.Microsecond)
}

// ConsumerInfo seems to being called quite a bit more than we had anticipated.
// Under certain circumstances, since we reset num pending, this can be very costly.
// We will use the fast path to alleviate that performance bottleneck but also make
// sure we are still being accurate.
func TestNoRaceJetStreamClusterConsumerInfoSpeed(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	c.waitOnLeader()
	server := c.randomNonLeader()

	nc, js := jsClientConnect(t, server)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"events.>"},
		Replicas: 3,
	})
	require_NoError(t, err)

	// The issue is compounded when we have lots of different subjects captured
	// by a terminal fwc. The consumer will have a terminal pwc.
	// Here make all subjects unique.

	sub, err := js.PullSubscribe("events.*", "DLC")
	require_NoError(t, err)

	toSend := 250_000
	for i := 0; i < toSend; i++ {
		subj := fmt.Sprintf("events.%d", i+1)
		js.PublishAsync(subj, []byte("ok"))
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	checkNumPending := func(expected int) {
		t.Helper()
		start := time.Now()
		ci, err := js.ConsumerInfo("TEST", "DLC")
		require_NoError(t, err)
		// Make sure these are fast now.
		if elapsed := time.Since(start); elapsed > 5*time.Millisecond {
			t.Fatalf("ConsumerInfo took too long: %v", elapsed)
		}
		// Make sure pending == expected.
		if ci.NumPending != uint64(expected) {
			t.Fatalf("Expected %d NumPending, got %d", expected, ci.NumPending)
		}
	}
	// Make sure in simple case it is correct.
	checkNumPending(toSend)

	// Do a few acks.
	toAck := 25
	for _, m := range fetchMsgs(t, sub, 25, time.Second) {
		err = m.AckSync()
		require_NoError(t, err)
	}
	checkNumPending(toSend - toAck)

	// Now do a purge such that we only keep so many.
	// We want to make sure we do the right thing here and have correct calculations.
	toKeep := 100_000
	err = js.PurgeStream("TEST", &nats.StreamPurgeRequest{Keep: uint64(toKeep)})
	require_NoError(t, err)

	checkNumPending(toKeep)
}

func TestNoRaceJetStreamKVAccountWithServerRestarts(t *testing.T) {
	// Uncomment to run. Needs fast machine to not time out on KeyValue lookup.
	skip(t)

	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	_, err := js.CreateKeyValue(&nats.KeyValueConfig{
		Bucket:   "TEST",
		Replicas: 3,
	})
	require_NoError(t, err)

	npubs := 10_000
	par := 8
	iter := 2
	nsubjs := 250

	wg := sync.WaitGroup{}
	putKeys := func() {
		wg.Add(1)
		go func() {
			defer wg.Done()
			nc, js := jsClientConnect(t, c.randomServer())
			defer nc.Close()
			kv, err := js.KeyValue("TEST")
			require_NoError(t, err)

			for i := 0; i < npubs; i++ {
				subj := fmt.Sprintf("KEY-%d", rand.Intn(nsubjs))
				if _, err := kv.PutString(subj, "hello"); err != nil {
					nc, js := jsClientConnect(t, c.randomServer())
					defer nc.Close()
					kv, err = js.KeyValue("TEST")
					require_NoError(t, err)
				}
			}
		}()
	}

	restartServers := func() {
		time.Sleep(2 * time.Second)
		// Rotate through and restart the servers.
		for _, server := range c.servers {
			server.Shutdown()
			restarted := c.restartServer(server)
			checkFor(t, time.Second, 200*time.Millisecond, func() error {
				hs := restarted.healthz(&HealthzOptions{
					JSEnabled:    true,
					JSServerOnly: true,
				})
				if hs.Error != _EMPTY_ {
					return errors.New(hs.Error)
				}
				return nil
			})
		}
		c.waitOnLeader()
		c.waitOnStreamLeader(globalAccountName, "KV_TEST")
	}

	for n := 0; n < iter; n++ {
		for i := 0; i < par; i++ {
			putKeys()
		}
		restartServers()
	}
	wg.Wait()

	nc, js = jsClientConnect(t, c.randomServer())
	defer nc.Close()

	si, err := js.StreamInfo("KV_TEST")
	require_NoError(t, err)
	require_True(t, si.State.NumSubjects == uint64(nsubjs))
}

// Test for consumer create when the subject cardinality is high and the
// consumer is filtered with a wildcard that forces linear scans.
// We have an optimization to use in memory structures in filestore to speed up.
// Only if asking to scan all (DeliverAll).
func TestNoRaceJetStreamConsumerCreateTimeNumPending(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"events.>"},
	})
	require_NoError(t, err)

	n := 500_000
	msg := bytes.Repeat([]byte("X"), 8*1024)

	for i := 0; i < n; i++ {
		subj := fmt.Sprintf("events.%d", rand.Intn(100_000))
		js.PublishAsync(subj, msg)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
	}

	// Should stay under 5ms now, but for Travis variability say 50ms.
	threshold := 50 * time.Millisecond

	start := time.Now()
	_, err = js.PullSubscribe("events.*", "dlc")
	require_NoError(t, err)
	if elapsed := time.Since(start); elapsed > threshold {
		t.Fatalf("Consumer create took longer than expected, %v vs %v", elapsed, threshold)
	}

	start = time.Now()
	_, err = js.PullSubscribe("events.99999", "xxx")
	require_NoError(t, err)
	if elapsed := time.Since(start); elapsed > threshold {
		t.Fatalf("Consumer create took longer than expected, %v vs %v", elapsed, threshold)
	}

	start = time.Now()
	_, err = js.PullSubscribe(">", "zzz")
	require_NoError(t, err)
	if elapsed := time.Since(start); elapsed > threshold {
		t.Fatalf("Consumer create took longer than expected, %v vs %v", elapsed, threshold)
	}
}

func TestNoRaceJetStreamClusterGhostConsumers(t *testing.T) {
	consumerNotActiveStartInterval = time.Second * 5
	defer func() {
		consumerNotActiveStartInterval = defaultConsumerNotActiveStartInterval
	}()

	c := createJetStreamClusterExplicit(t, "GHOST", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"events.>"},
		Replicas: 3,
	})
	require_NoError(t, err)

	for i := 0; i < 10; i++ {
		for j := 0; j < 10; j++ {
			require_NoError(t, nc.Publish(fmt.Sprintf("events.%d.%d", i, j), []byte(`test`)))
		}
	}

	fetch := func(id int) {
		subject := fmt.Sprintf("events.%d.*", id)
		subscription, err := js.PullSubscribe(subject,
			_EMPTY_, // ephemeral consumer
			nats.DeliverAll(),
			nats.ReplayInstant(),
			nats.BindStream("TEST"),
			nats.ConsumerReplicas(1),
			nats.ConsumerMemoryStorage(),
		)
		if err != nil {
			return
		}
		defer subscription.Unsubscribe()

		info, err := subscription.ConsumerInfo()
		if err != nil {
			return
		}

		subscription.Fetch(int(info.NumPending))
	}

	replay := func(ctx context.Context, id int) {
		for {
			select {
			case <-ctx.Done():
				return
			default:
				fetch(id)
			}
		}
	}

	ctx, cancel := context.WithCancel(context.Background())

	go replay(ctx, 0)
	go replay(ctx, 1)
	go replay(ctx, 2)
	go replay(ctx, 3)
	go replay(ctx, 4)
	go replay(ctx, 5)
	go replay(ctx, 6)
	go replay(ctx, 7)
	go replay(ctx, 8)
	go replay(ctx, 9)

	time.Sleep(5 * time.Second)

	for _, server := range c.servers {
		server.Shutdown()
		restarted := c.restartServer(server)
		checkFor(t, time.Second, 200*time.Millisecond, func() error {
			hs := restarted.healthz(&HealthzOptions{
				JSEnabled:    true,
				JSServerOnly: true,
			})
			if hs.Error != _EMPTY_ {
				return errors.New(hs.Error)
			}
			return nil
		})
		c.waitOnStreamLeader(globalAccountName, "TEST")
		time.Sleep(time.Second * 2)
		go replay(ctx, 5)
		go replay(ctx, 6)
		go replay(ctx, 7)
		go replay(ctx, 8)
		go replay(ctx, 9)
	}

	time.Sleep(5 * time.Second)
	cancel()

	// Check we don't report missing consumers.
	subj := fmt.Sprintf(JSApiConsumerListT, "TEST")
	checkFor(t, 20*time.Second, 200*time.Millisecond, func() error {
		// Request will take at most 4 seconds if some consumers can't be found.
		m, err := nc.Request(subj, nil, 5*time.Second)
		if err != nil {
			return err
		}
		var resp JSApiConsumerListResponse
		require_NoError(t, json.Unmarshal(m.Data, &resp))
		if len(resp.Missing) == 0 {
			return nil
		}
		return fmt.Errorf("Still have missing: %+v", resp.Missing)
	})

	// Also check all servers agree on the available consumer assignments.
	// It could be the above check passes, i.e. our meta leader thinks all is okay, but other servers actually drifted.
	checkFor(t, 5*time.Second, 200*time.Millisecond, func() error {
		var previousConsumers []string
		for _, s := range c.servers {
			sjs := s.getJetStream()
			sjs.mu.Lock()
			cc := sjs.cluster
			sa := cc.streams[globalAccountName]["TEST"]
			var consumers []string
			for cName := range sa.consumers {
				consumers = append(consumers, cName)
			}
			sjs.mu.Unlock()
			slices.Sort(consumers)
			if previousConsumers != nil && !slices.Equal(previousConsumers, consumers) {
				return fmt.Errorf("Consumer mismatch:\n- previous: %v\n- actual  : %v\n", previousConsumers, consumers)
			}
			previousConsumers = consumers
		}
		return nil
	})
}

// This is to test a publish slowdown and general instability experienced in a setup similar to this.
// We have feeder streams that are all sourced to an aggregate stream. All streams are interest retention.
// We want to monitor the avg publish time for the sync publishers to the feeder streams, the ingest rate to
// the aggregate stream, and general health of the consumers on the aggregate stream.
// Target publish rate is ~2k/s with publish time being ~40-60ms but remaining stable.
// We can also simulate max redeliveries that create interior deletes in streams.
func TestNoRaceJetStreamClusterF3Setup(t *testing.T) {
	// Uncomment to run. Needs to be on a pretty big machine. Do not want as part of Travis tests atm.
	skip(t)

	// These and the settings below achieve ~60ms pub time on avg and ~2k msgs per sec inbound to the aggregate stream.
	// On my machine though.
	np := clusterProxy{
		rtt:  2 * time.Millisecond,
		up:   1 * 1024 * 1024 * 1024, // 1gbit
		down: 1 * 1024 * 1024 * 1024, // 1gbit
	}

	// Test params.
	numSourceStreams := 20
	numConsumersPerSource := 1
	numPullersPerConsumer := 50
	numPublishers := 100
	setHighStartSequence := false
	simulateMaxRedeliveries := false
	maxBadPubTimes := uint32(20)
	badPubThresh := 500 * time.Millisecond
	testTime := 5 * time.Minute // make sure to do --timeout=65m

	t.Logf("Starting Test: Total Test Time %v", testTime)

	c := createJetStreamClusterWithNetProxy(t, "R3S", 3, &np)
	defer c.shutdown()

	// Do some quick sanity checking for latency stuff.
	{
		nc, js := jsClientConnect(t, c.randomServer())
		defer nc.Close()

		_, err := js.AddStream(&nats.StreamConfig{
			Name:      "TEST",
			Replicas:  3,
			Subjects:  []string{"foo"},
			Retention: nats.InterestPolicy,
		})
		require_NoError(t, err)
		defer js.DeleteStream("TEST")

		sl := c.streamLeader(globalAccountName, "TEST")
		nc, js = jsClientConnect(t, sl)
		defer nc.Close()
		start := time.Now()
		_, err = js.Publish("foo", []byte("hello"))
		require_NoError(t, err)
		// This is best case, and with client connection being close to free, this should be at least > rtt
		if elapsed := time.Since(start); elapsed < np.rtt {
			t.Fatalf("Expected publish time to be > %v, got %v", np.rtt, elapsed)
		}

		nl := c.randomNonStreamLeader(globalAccountName, "TEST")
		nc, js = jsClientConnect(t, nl)
		defer nc.Close()
		start = time.Now()
		_, err = js.Publish("foo", []byte("hello"))
		require_NoError(t, err)
		// This is worst case, meaning message has to travel to leader, then to fastest replica, then back.
		// So should be at 3x rtt, so check at least > 2x rtt.
		if elapsed := time.Since(start); elapsed < 2*np.rtt {
			t.Fatalf("Expected publish time to be > %v, got %v", 2*np.rtt, elapsed)
		}
	}

	// Setup source streams.
	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	t.Logf("Creating %d Source Streams", numSourceStreams)

	var sources []string
	wg := sync.WaitGroup{}
	for i := 0; i < numSourceStreams; i++ {
		sname := fmt.Sprintf("EVENT-%s", nuid.Next())
		sources = append(sources, sname)
		wg.Add(1)
		go func(stream string) {
			defer wg.Done()
			t.Logf("  %q", stream)
			subj := fmt.Sprintf("%s.>", stream)
			_, err := js.AddStream(&nats.StreamConfig{
				Name:      stream,
				Subjects:  []string{subj},
				Replicas:  3,
				Retention: nats.InterestPolicy,
			})
			require_NoError(t, err)
			for j := 0; j < numConsumersPerSource; j++ {
				consumer := fmt.Sprintf("C%d", j)
				_, err := js.Subscribe(_EMPTY_, func(msg *nats.Msg) {
					msg.Ack()
				}, nats.BindStream(stream), nats.Durable(consumer), nats.ManualAck())
				require_NoError(t, err)
			}
		}(sname)
	}
	wg.Wait()

	var streamSources []*nats.StreamSource
	for _, src := range sources {
		streamSources = append(streamSources, &nats.StreamSource{Name: src})

	}

	t.Log("Creating Aggregate Stream")

	// Now create the aggregate stream.
	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "EVENTS",
		Replicas:  3,
		Retention: nats.InterestPolicy,
		Sources:   streamSources,
	})
	require_NoError(t, err)

	// Set first sequence to a high number.
	if setHighStartSequence {
		require_NoError(t, js.PurgeStream("EVENTS", &nats.StreamPurgeRequest{Sequence: 32_000_001}))
	}

	// Now create 2 pull consumers.
	_, err = js.PullSubscribe(_EMPTY_, "C1",
		nats.BindStream("EVENTS"),
		nats.MaxDeliver(1),
		nats.AckWait(10*time.Second),
		nats.ManualAck(),
	)
	require_NoError(t, err)

	_, err = js.PullSubscribe(_EMPTY_, "C2",
		nats.BindStream("EVENTS"),
		nats.MaxDeliver(1),
		nats.AckWait(10*time.Second),
		nats.ManualAck(),
	)
	require_NoError(t, err)

	t.Logf("Creating %d x 2 Pull Subscribers", numPullersPerConsumer)

	// Now create the pullers.
	for _, subName := range []string{"C1", "C2"} {
		for i := 0; i < numPullersPerConsumer; i++ {
			go func(subName string) {
				nc, js := jsClientConnect(t, c.randomServer())
				defer nc.Close()

				sub, err := js.PullSubscribe(_EMPTY_, subName,
					nats.BindStream("EVENTS"),
					nats.MaxDeliver(1),
					nats.AckWait(10*time.Second),
					nats.ManualAck(),
				)
				require_NoError(t, err)

				for {
					msgs, err := sub.Fetch(25, nats.MaxWait(2*time.Second))
					if err != nil && err != nats.ErrTimeout {
						t.Logf("Exiting pull subscriber %q: %v", subName, err)
						return
					}
					// Shuffle
					rand.Shuffle(len(msgs), func(i, j int) { msgs[i], msgs[j] = msgs[j], msgs[i] })

					// Wait for a random interval up to 100ms.
					time.Sleep(time.Duration(rand.Intn(100)) * time.Millisecond)

					for _, m := range msgs {
						// If we want to simulate max redeliveries being hit, since not acking
						// once will cause it due to subscriber setup.
						// 100_000 == 0.01%
						if simulateMaxRedeliveries && rand.Intn(100_000) == 0 {
							md, err := m.Metadata()
							require_NoError(t, err)
							t.Logf("** Skipping Ack: %d **", md.Sequence.Stream)
						} else {
							m.Ack()
						}
					}
				}
			}(subName)
		}
	}

	// Now create feeder publishers.
	eventTypes := []string{"PAYMENT", "SUBMISSION", "CANCEL"}

	msg := make([]byte, 2*1024) // 2k payload
	crand.Read(msg)

	// For tracking pub times.
	var pubs int
	var totalPubTime time.Duration
	var pmu sync.Mutex
	last := time.Now()

	updatePubStats := func(elapsed time.Duration) {
		pmu.Lock()
		defer pmu.Unlock()
		// Reset every 5s
		if time.Since(last) > 5*time.Second {
			pubs = 0
			totalPubTime = 0
			last = time.Now()
		}
		pubs++
		totalPubTime += elapsed
	}
	avgPubTime := func() time.Duration {
		pmu.Lock()
		np := pubs
		tpt := totalPubTime
		pmu.Unlock()
		return tpt / time.Duration(np)
	}

	t.Logf("Creating %d Publishers", numPublishers)

	var numLimitsExceeded atomic.Uint32
	errCh := make(chan error, 100)

	for i := 0; i < numPublishers; i++ {
		go func() {
			nc, js := jsClientConnect(t, c.randomServer())
			defer nc.Close()

			for {
				// Grab a random source stream
				stream := sources[rand.Intn(len(sources))]
				// Grab random event type.
				evt := eventTypes[rand.Intn(len(eventTypes))]
				subj := fmt.Sprintf("%s.%s", stream, evt)
				start := time.Now()
				_, err := js.Publish(subj, msg)
				if err != nil {
					t.Logf("Exiting publisher: %v", err)
					return
				}
				elapsed := time.Since(start)
				if elapsed > badPubThresh {
					t.Logf("Publish time took more than expected: %v", elapsed)
					numLimitsExceeded.Add(1)
					if ne := numLimitsExceeded.Load(); ne > maxBadPubTimes {
						errCh <- fmt.Errorf("Too many exceeded times on publish: %d", ne)
						return
					}
				}
				updatePubStats(elapsed)
			}
		}()
	}

	t.Log("Creating Monitoring Routine - Data in ~10s")

	// Create monitoring routine.
	go func() {
		nc, js := jsClientConnect(t, c.randomServer())
		defer nc.Close()

		fseq, lseq := uint64(0), uint64(0)
		for {
			// Grab consumers
			var minAckFloor uint64 = math.MaxUint64
			for _, consumer := range []string{"C1", "C2"} {
				ci, err := js.ConsumerInfo("EVENTS", consumer)
				if err != nil {
					t.Logf("Exiting Monitor: %v", err)
					return
				}
				if lseq > 0 {
					t.Logf("%s:\n  Delivered:\t%d\n  AckFloor:\t%d\n  AckPending:\t%d\n  NumPending:\t%d",
						consumer, ci.Delivered.Stream, ci.AckFloor.Stream, ci.NumAckPending, ci.NumPending)
				}
				if ci.AckFloor.Stream < minAckFloor {
					minAckFloor = ci.AckFloor.Stream
				}
			}
			// Now grab aggregate stream state.
			si, err := js.StreamInfo("EVENTS")
			if err != nil {
				t.Logf("Exiting Monitor: %v", err)
				return
			}
			state := si.State
			if lseq != 0 {
				t.Logf("Stream:\n  Msgs: \t%d\n  First:\t%d\n  Last: \t%d\n  Deletes:\t%d\n",
					state.Msgs, state.FirstSeq, state.LastSeq, state.NumDeleted)
				t.Logf("Publish Stats:\n  Msgs/s:\t%0.2f\n  Avg Pub:\t%v\n\n", float64(si.State.LastSeq-lseq)/5.0, avgPubTime())
				if si.State.FirstSeq < minAckFloor && si.State.FirstSeq == fseq {
					t.Log("Stream first seq < minimum ack floor")
				}
			}
			fseq, lseq = si.State.FirstSeq, si.State.LastSeq
			time.Sleep(5 * time.Second)
		}

	}()

	select {
	case e := <-errCh:
		t.Fatal(e)
	case <-time.After(testTime):
		t.Fatalf("Did not receive completion signal")
	}
}

// Unbalanced stretch cluster.
// S2 (stream leader) will have a slow path to S1 (via proxy) and S3 (consumer leader) will have a fast path.
//
//	 Route Ports
//		"S1": 14622
//		"S2": 15622
//		"S3": 16622
func createStretchUnbalancedCluster(t testing.TB) (c *cluster, np *netProxy) {
	t.Helper()

	tmpl := `
	listen: 127.0.0.1:-1
	server_name: %s
	jetstream: {max_mem_store: 256MB, max_file_store: 2GB, store_dir: '%s'}

	cluster {
		name: "F3"
		listen: 127.0.0.1:%d
		routes = [%s]
	}

	accounts {
		$SYS { users = [ { user: "admin", pass: "s3cr3t!" } ] }
	}
	`
	// Do these in order, S1, S2 (proxy) then S3.
	c = &cluster{t: t, servers: make([]*Server, 3), opts: make([]*Options, 3), name: "F3"}

	// S1
	conf := fmt.Sprintf(tmpl, "S1", t.TempDir(), 14622, "route://127.0.0.1:15622, route://127.0.0.1:16622")
	c.servers[0], c.opts[0] = RunServerWithConfig(createConfFile(t, []byte(conf)))

	// S2
	// Create the proxy first. Connect this to S1. Make it slow, e.g. 5ms RTT.
	np = createNetProxy(1*time.Millisecond, 1024*1024*1024, 1024*1024*1024, "route://127.0.0.1:14622", true)
	routes := fmt.Sprintf("%s, route://127.0.0.1:16622", np.routeURL())
	conf = fmt.Sprintf(tmpl, "S2", t.TempDir(), 15622, routes)
	c.servers[1], c.opts[1] = RunServerWithConfig(createConfFile(t, []byte(conf)))

	// S3
	conf = fmt.Sprintf(tmpl, "S3", t.TempDir(), 16622, "route://127.0.0.1:14622, route://127.0.0.1:15622")
	c.servers[2], c.opts[2] = RunServerWithConfig(createConfFile(t, []byte(conf)))

	c.checkClusterFormed()
	c.waitOnClusterReady()

	return c, np
}

// We test an interest based stream that has a cluster with a node with asymmetric paths from
// the stream leader and the consumer leader such that the consumer leader path is fast and
// replicated acks arrive sooner then the actual message. This path was considered, but also
// categorized as very rare and was expensive as it tried to forward a new stream msg delete
// proposal to the original stream leader. It now will deal with the issue locally and not
// slow down the ingest rate to the stream's publishers.
func TestNoRaceJetStreamClusterDifferentRTTInterestBasedStreamSetup(t *testing.T) {
	// Uncomment to run. Do not want as part of Travis tests atm.
	skip(t)

	c, np := createStretchUnbalancedCluster(t)
	defer c.shutdown()
	defer np.stop()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	// Now create the stream.
	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "EVENTS",
		Subjects:  []string{"EV.>"},
		Replicas:  3,
		Retention: nats.InterestPolicy,
	})
	require_NoError(t, err)

	// Make sure it's leader is on S2.
	sl := c.servers[1]
	checkFor(t, 20*time.Second, 200*time.Millisecond, func() error {
		c.waitOnStreamLeader(globalAccountName, "EVENTS")
		if s := c.streamLeader(globalAccountName, "EVENTS"); s != sl {
			s.JetStreamStepdownStream(globalAccountName, "EVENTS")
			return fmt.Errorf("Server %s is not stream leader yet", sl)
		}
		return nil
	})

	// Now create the consumer.
	_, err = js.PullSubscribe(_EMPTY_, "C", nats.BindStream("EVENTS"), nats.ManualAck())
	require_NoError(t, err)

	// Make sure the consumer leader is on S3.
	cl := c.servers[2]
	checkFor(t, 20*time.Second, 200*time.Millisecond, func() error {
		c.waitOnConsumerLeader(globalAccountName, "EVENTS", "C")
		if s := c.consumerLeader(globalAccountName, "EVENTS", "C"); s != cl {
			s.JetStreamStepdownConsumer(globalAccountName, "EVENTS", "C")
			return fmt.Errorf("Server %s is not consumer leader yet", cl)
		}
		return nil
	})

	go func(js nats.JetStream) {
		sub, err := js.PullSubscribe(_EMPTY_, "C", nats.BindStream("EVENTS"), nats.ManualAck())
		require_NoError(t, err)

		for {
			msgs, err := sub.Fetch(100, nats.MaxWait(2*time.Second))
			if err != nil && err != nats.ErrTimeout {
				return
			}
			// Shuffle
			rand.Shuffle(len(msgs), func(i, j int) { msgs[i], msgs[j] = msgs[j], msgs[i] })
			for _, m := range msgs {
				m.Ack()
			}
		}
	}(js)

	numPublishers := 25
	pubThresh := 2 * time.Second
	var maxExceeded atomic.Int64
	errCh := make(chan error, numPublishers)
	wg := sync.WaitGroup{}

	msg := make([]byte, 2*1024) // 2k payload
	crand.Read(msg)

	// Publishers.
	for i := 0; i < numPublishers; i++ {
		wg.Add(1)
		go func(iter int) {
			defer wg.Done()

			// Connect to random, the slow ones will be connected to the slow node.
			// But if you connect them all there it will pass.
			s := c.randomServer()
			nc, js := jsClientConnect(t, s)
			defer nc.Close()

			for i := 0; i < 1_000; i++ {
				start := time.Now()
				_, err := js.Publish("EV.PAID", msg)
				if err != nil {
					errCh <- fmt.Errorf("Publish error: %v", err)
					return
				}
				if elapsed := time.Since(start); elapsed > pubThresh {
					errCh <- fmt.Errorf("Publish time exceeded")
					if int64(elapsed) > maxExceeded.Load() {
						maxExceeded.Store(int64(elapsed))
					}
					return
				}
			}
		}(i)
	}

	wg.Wait()

	select {
	case e := <-errCh:
		t.Fatalf("%v: threshold is %v, maximum seen: %v", e, pubThresh, time.Duration(maxExceeded.Load()))
	default:
	}
}

func TestNoRaceJetStreamInterestStreamCheckInterestRaceBug(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "TEST",
		Subjects:  []string{"foo"},
		Replicas:  3,
		Retention: nats.InterestPolicy,
	})
	require_NoError(t, err)

	numConsumers := 10
	for i := 0; i < numConsumers; i++ {
		nc, js := jsClientConnect(t, c.randomServer())
		defer nc.Close()

		_, err = js.Subscribe("foo", func(m *nats.Msg) {
			m.Ack()
		}, nats.Durable(fmt.Sprintf("C%d", i)), nats.ManualAck())
		require_NoError(t, err)
	}

	numToSend := 10_000
	for i := 0; i < numToSend; i++ {
		_, err := js.PublishAsync("foo", nil, nats.StallWait(800*time.Millisecond))
		require_NoError(t, err)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(20 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	// Wait til ackfloor is correct for all consumers.
	checkFor(t, 20*time.Second, 100*time.Millisecond, func() error {
		for _, s := range c.servers {
			mset, err := s.GlobalAccount().lookupStream("TEST")
			require_NoError(t, err)

			mset.mu.RLock()
			defer mset.mu.RUnlock()

			require_True(t, len(mset.consumers) == numConsumers)

			for _, o := range mset.consumers {
				state, err := o.store.State()
				require_NoError(t, err)
				if state.AckFloor.Stream != uint64(numToSend) {
					return fmt.Errorf("Ackfloor not correct yet")
				}
			}
		}
		return nil
	})

	for _, s := range c.servers {
		mset, err := s.GlobalAccount().lookupStream("TEST")
		require_NoError(t, err)

		mset.mu.RLock()
		defer mset.mu.RUnlock()

		state := mset.state()
		require_True(t, state.Msgs == 0)
		require_True(t, state.FirstSeq == uint64(numToSend+1))
	}
}

func TestNoRaceJetStreamClusterInterestStreamConsistencyAfterRollingRestart(t *testing.T) {
	// Uncomment to run. Needs to be on a big machine. Do not want as part of Travis tests atm.
	skip(t)

	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	numStreams := 200
	numConsumersPer := 5
	numPublishers := 10

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	qch := make(chan bool)

	var mm sync.Mutex
	ackMap := make(map[string]map[uint64][]string)

	addAckTracking := func(seq uint64, stream, consumer string) {
		mm.Lock()
		defer mm.Unlock()
		sam := ackMap[stream]
		if sam == nil {
			sam = make(map[uint64][]string)
			ackMap[stream] = sam
		}
		sam[seq] = append(sam[seq], consumer)
	}

	doPullSubscriber := func(stream, consumer, filter string) {
		nc, js := jsClientConnect(t, c.randomServer())
		defer nc.Close()

		var err error
		var sub *nats.Subscription
		timeout := time.Now().Add(5 * time.Second)
		for time.Now().Before(timeout) {
			sub, err = js.PullSubscribe(filter, consumer, nats.BindStream(stream), nats.ManualAck())
			if err == nil {
				break
			}
		}
		if err != nil {
			t.Logf("Error on pull subscriber: %v", err)
			return
		}

		for {
			select {
			case <-time.After(500 * time.Millisecond):
				msgs, err := sub.Fetch(100, nats.MaxWait(time.Second))
				if err != nil {
					continue
				}
				// Shuffle
				rand.Shuffle(len(msgs), func(i, j int) { msgs[i], msgs[j] = msgs[j], msgs[i] })
				for _, m := range msgs {
					meta, err := m.Metadata()
					require_NoError(t, err)
					m.Ack()
					addAckTracking(meta.Sequence.Stream, stream, consumer)
					if meta.NumDelivered > 1 {
						t.Logf("Got a msg redelivered %d for sequence %d on %q %q\n", meta.NumDelivered, meta.Sequence.Stream, stream, consumer)
					}
				}
			case <-qch:
				nc.Flush()
				return
			}
		}
	}

	// Setup
	wg := sync.WaitGroup{}
	for i := 0; i < numStreams; i++ {
		wg.Add(1)
		go func(stream string) {
			defer wg.Done()
			subj := fmt.Sprintf("%s.>", stream)
			_, err := js.AddStream(&nats.StreamConfig{
				Name:      stream,
				Subjects:  []string{subj},
				Replicas:  3,
				Retention: nats.InterestPolicy,
			})
			require_NoError(t, err)
			for i := 0; i < numConsumersPer; i++ {
				consumer := fmt.Sprintf("C%d", i)
				filter := fmt.Sprintf("%s.%d", stream, i)
				_, err = js.AddConsumer(stream, &nats.ConsumerConfig{
					Durable:       consumer,
					FilterSubject: filter,
					AckPolicy:     nats.AckExplicitPolicy,
					AckWait:       2 * time.Second,
				})
				require_NoError(t, err)
				c.waitOnConsumerLeader(globalAccountName, stream, consumer)
				go doPullSubscriber(stream, consumer, filter)
			}
		}(fmt.Sprintf("A-%d", i))
	}
	wg.Wait()

	msg := make([]byte, 2*1024) // 2k payload
	crand.Read(msg)

	// Controls if publishing is on or off.
	var pubActive atomic.Bool

	doPublish := func() {
		nc, js := jsClientConnect(t, c.randomServer())
		defer nc.Close()

		for {
			select {
			case <-time.After(100 * time.Millisecond):
				if pubActive.Load() {
					for i := 0; i < numStreams; i++ {
						for j := 0; j < numConsumersPer; j++ {
							subj := fmt.Sprintf("A-%d.%d", i, j)
							// Don't care about errors here for this test.
							js.Publish(subj, msg)
						}
					}
				}
			case <-qch:
				return
			}
		}
	}

	pubActive.Store(true)

	for i := 0; i < numPublishers; i++ {
		go doPublish()
	}

	// Let run for a bit.
	time.Sleep(20 * time.Second)

	// Do a rolling restart.
	for _, s := range c.servers {
		t.Logf("Shutdown %v\n", s)
		s.Shutdown()
		s.WaitForShutdown()
		time.Sleep(20 * time.Second)
		t.Logf("Restarting %v\n", s)
		s = c.restartServer(s)
		c.waitOnServerHealthz(s)
	}

	// Let run for a bit longer.
	time.Sleep(10 * time.Second)

	// Stop pubs.
	pubActive.Store(false)

	// Let settle.
	time.Sleep(10 * time.Second)
	close(qch)
	time.Sleep(20 * time.Second)

	nc, js = jsClientConnect(t, c.randomServer())
	defer nc.Close()

	minAckFloor := func(stream string) (uint64, string) {
		var maf uint64 = math.MaxUint64
		var consumer string
		for i := 0; i < numConsumersPer; i++ {
			cname := fmt.Sprintf("C%d", i)
			ci, err := js.ConsumerInfo(stream, cname)
			require_NoError(t, err)
			if ci.AckFloor.Stream < maf {
				maf = ci.AckFloor.Stream
				consumer = cname
			}
		}
		return maf, consumer
	}

	checkStreamAcks := func(stream string) {
		mm.Lock()
		defer mm.Unlock()
		if sam := ackMap[stream]; sam != nil {
			for seq := 1; ; seq++ {
				acks := sam[uint64(seq)]
				if acks == nil {
					if sam[uint64(seq+1)] != nil {
						t.Logf("Missing an ack on stream %q for sequence %d\n", stream, seq)
					} else {
						break
					}
				}
				if len(acks) > 1 {
					t.Logf("Multiple acks for %d which is not expected: %+v", seq, acks)
				}
			}
		}
	}

	// Now check all streams such that their first sequence is equal to the minimum of all consumers.
	for i := 0; i < numStreams; i++ {
		stream := fmt.Sprintf("A-%d", i)
		si, err := js.StreamInfo(stream)
		require_NoError(t, err)

		if maf, consumer := minAckFloor(stream); maf > si.State.FirstSeq {
			t.Logf("\nBAD STATE DETECTED FOR %q, CHECKING OTHER SERVERS! ACK %d vs %+v LEADER %v, CL FOR %q %v\n",
				stream, maf, si.State, c.streamLeader(globalAccountName, stream), consumer, c.consumerLeader(globalAccountName, stream, consumer))

			t.Logf("TEST ACKS %+v\n", ackMap)

			checkStreamAcks(stream)

			for _, s := range c.servers {
				mset, err := s.GlobalAccount().lookupStream(stream)
				require_NoError(t, err)
				state := mset.state()
				t.Logf("Server %v Stream STATE %+v\n", s, state)

				var smv StoreMsg
				if sm, err := mset.store.LoadMsg(state.FirstSeq, &smv); err == nil {
					t.Logf("Subject for msg %d is %q", state.FirstSeq, sm.subj)
				} else {
					t.Logf("Could not retrieve msg for %d: %v", state.FirstSeq, err)
				}

				if len(mset.preAcks) > 0 {
					t.Logf("%v preAcks %+v\n", s, mset.preAcks)
				}

				for _, o := range mset.consumers {
					ostate, err := o.store.State()
					require_NoError(t, err)
					t.Logf("Consumer STATE for %q is %+v\n", o.name, ostate)
				}
			}
			t.Fatalf("BAD STATE: ACKFLOOR > FIRST %d vs %d\n", maf, si.State.FirstSeq)
		}
	}
}

func TestNoRaceFileStoreNumPending(t *testing.T) {
	// No need for all permutations here.
	storeDir := t.TempDir()
	fcfg := FileStoreConfig{
		StoreDir:  storeDir,
		BlockSize: 2 * 1024, // Create many blocks on purpose.
	}
	fs, err := newFileStore(fcfg, StreamConfig{Name: "zzz", Subjects: []string{"*.*.*.*"}, Storage: FileStorage})
	require_NoError(t, err)
	defer fs.Stop()

	tokens := []string{"foo", "bar", "baz"}
	genSubj := func() string {
		return fmt.Sprintf("%s.%s.%s.%s",
			tokens[rand.Intn(len(tokens))],
			tokens[rand.Intn(len(tokens))],
			tokens[rand.Intn(len(tokens))],
			tokens[rand.Intn(len(tokens))],
		)
	}

	for i := 0; i < 50_000; i++ {
		subj := genSubj()
		_, _, err := fs.StoreMsg(subj, nil, []byte("Hello World"))
		require_NoError(t, err)
	}

	state := fs.State()

	// Scan one by one for sanity check against other calculations.
	sanityCheck := func(sseq uint64, filter string) SimpleState {
		t.Helper()
		var ss SimpleState
		var smv StoreMsg
		// For here we know 0 is invalid, set to 1.
		if sseq == 0 {
			sseq = 1
		}
		for seq := sseq; seq <= state.LastSeq; seq++ {
			sm, err := fs.LoadMsg(seq, &smv)
			if err != nil {
				t.Logf("Encountered error %v loading sequence: %d", err, seq)
				continue
			}
			if subjectIsSubsetMatch(sm.subj, filter) {
				ss.Msgs++
				ss.Last = seq
				if ss.First == 0 || seq < ss.First {
					ss.First = seq
				}
			}
		}
		return ss
	}

	check := func(sseq uint64, filter string) {
		t.Helper()
		np, lvs := fs.NumPending(sseq, filter, false)
		ss := fs.FilteredState(sseq, filter)
		sss := sanityCheck(sseq, filter)
		if lvs != state.LastSeq {
			t.Fatalf("Expected NumPending to return valid through last of %d but got %d", state.LastSeq, lvs)
		}
		if ss.Msgs != np {
			t.Fatalf("NumPending of %d did not match ss.Msgs of %d", np, ss.Msgs)
		}
		if ss != sss {
			t.Fatalf("Failed sanity check, expected %+v got %+v", sss, ss)
		}
	}

	sanityCheckLastOnly := func(sseq uint64, filter string) SimpleState {
		t.Helper()
		var ss SimpleState
		var smv StoreMsg
		// For here we know 0 is invalid, set to 1.
		if sseq == 0 {
			sseq = 1
		}
		seen := make(map[string]bool)
		for seq := state.LastSeq; seq >= sseq; seq-- {
			sm, err := fs.LoadMsg(seq, &smv)
			if err != nil {
				t.Logf("Encountered error %v loading sequence: %d", err, seq)
				continue
			}
			if !seen[sm.subj] && subjectIsSubsetMatch(sm.subj, filter) {
				ss.Msgs++
				if ss.Last == 0 {
					ss.Last = seq
				}
				if ss.First == 0 || seq < ss.First {
					ss.First = seq
				}
				seen[sm.subj] = true
			}
		}
		return ss
	}

	checkLastOnly := func(sseq uint64, filter string) {
		t.Helper()
		np, lvs := fs.NumPending(sseq, filter, true)
		ss := sanityCheckLastOnly(sseq, filter)
		if lvs != state.LastSeq {
			t.Fatalf("Expected NumPending to return valid through last of %d but got %d", state.LastSeq, lvs)
		}
		if ss.Msgs != np {
			t.Fatalf("NumPending of %d did not match ss.Msgs of %d", np, ss.Msgs)
		}
	}

	startSeqs := []uint64{0, 1, 2, 200, 444, 555, 2222, 8888, 12_345, 28_222, 33_456, 44_400, 49_999}
	checkSubs := []string{"foo.>", "*.bar.>", "foo.bar.*.baz", "*.bar.>", "*.foo.bar.*", "foo.foo.bar.baz"}

	for _, filter := range checkSubs {
		for _, start := range startSeqs {
			check(start, filter)
			checkLastOnly(start, filter)
		}
	}
}

func TestNoRaceJetStreamClusterUnbalancedInterestMultipleConsumers(t *testing.T) {
	c, np := createStretchUnbalancedCluster(t)
	defer c.shutdown()
	defer np.stop()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	// Now create the stream.
	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "EVENTS",
		Subjects:  []string{"EV.>"},
		Replicas:  3,
		Retention: nats.InterestPolicy,
	})
	require_NoError(t, err)

	// Make sure it's leader is on S2.
	sl := c.servers[1]
	checkFor(t, 20*time.Second, 200*time.Millisecond, func() error {
		c.waitOnStreamLeader(globalAccountName, "EVENTS")
		if s := c.streamLeader(globalAccountName, "EVENTS"); s != sl {
			s.JetStreamStepdownStream(globalAccountName, "EVENTS")
			return fmt.Errorf("Server %s is not stream leader yet", sl)
		}
		return nil
	})

	// Create a fast ack consumer.
	_, err = js.Subscribe("EV.NEW", func(m *nats.Msg) {
		m.Ack()
	}, nats.Durable("C"), nats.ManualAck())
	require_NoError(t, err)

	// Make sure the consumer leader is on S3.
	cl := c.servers[2]
	checkFor(t, 20*time.Second, 200*time.Millisecond, func() error {
		c.waitOnConsumerLeader(globalAccountName, "EVENTS", "C")
		if s := c.consumerLeader(globalAccountName, "EVENTS", "C"); s != cl {
			s.JetStreamStepdownConsumer(globalAccountName, "EVENTS", "C")
			return fmt.Errorf("Server %s is not consumer leader yet", cl)
		}
		return nil
	})

	// Connect a client directly to the stream leader.
	nc, js = jsClientConnect(t, sl)
	defer nc.Close()

	// Now create a pull subscriber.
	sub, err := js.PullSubscribe("EV.NEW", "D", nats.ManualAck())
	require_NoError(t, err)

	// Make sure this consumer leader is on S1.
	cl = c.servers[0]
	checkFor(t, 20*time.Second, 200*time.Millisecond, func() error {
		c.waitOnConsumerLeader(globalAccountName, "EVENTS", "D")
		if s := c.consumerLeader(globalAccountName, "EVENTS", "D"); s != cl {
			s.JetStreamStepdownConsumer(globalAccountName, "EVENTS", "D")
			return fmt.Errorf("Server %s is not consumer leader yet", cl)
		}
		return nil
	})

	numToSend := 1000
	for i := 0; i < numToSend; i++ {
		_, err := js.PublishAsync("EV.NEW", nil)
		require_NoError(t, err)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(20 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	// Now make sure we can pull messages since we have not acked.
	// The bug is that the acks arrive on S1 faster then the messages but we want to
	// make sure we do not remove prematurely.
	msgs, err := sub.Fetch(100, nats.MaxWait(time.Second))
	require_NoError(t, err)
	require_Len(t, len(msgs), 100)
	for _, m := range msgs {
		m.AckSync()
	}

	ci, err := js.ConsumerInfo("EVENTS", "D")
	require_NoError(t, err)
	require_Equal(t, ci.NumPending, uint64(numToSend-100))
	require_Equal(t, ci.NumAckPending, 0)
	require_Equal(t, ci.Delivered.Stream, 100)
	require_Equal(t, ci.AckFloor.Stream, 100)

	// Check stream state on all servers.
	// Since acks result in messages to be removed through proposals,
	// it could take some time to be reflected in the stream state.
	checkFor(t, 5*time.Second, 500*time.Millisecond, func() error {
		for _, s := range c.servers {
			mset, err := s.GlobalAccount().lookupStream("EVENTS")
			if err != nil {
				return err
			}
			state := mset.state()
			if state.Msgs != 900 {
				return fmt.Errorf("expected state.Msgs=900, got %d", state.Msgs)
			}
			if state.FirstSeq != 101 {
				return fmt.Errorf("expected state.FirstSeq=101, got %d", state.FirstSeq)
			}
			if state.LastSeq != 1000 {
				return fmt.Errorf("expected state.LastSeq=1000, got %d", state.LastSeq)
			}
			if state.Consumers != 2 {
				return fmt.Errorf("expected state.Consumers=2, got %d", state.Consumers)
			}
		}
		return nil
	})

	msgs, err = sub.Fetch(900, nats.MaxWait(time.Second))
	require_NoError(t, err)
	require_Len(t, len(msgs), 900)
	for _, m := range msgs {
		m.AckSync()
	}

	// Let acks propagate.
	time.Sleep(250 * time.Millisecond)

	// Check final stream state on all servers.
	for _, s := range c.servers {
		mset, err := s.GlobalAccount().lookupStream("EVENTS")
		require_NoError(t, err)
		state := mset.state()
		require_Equal(t, state.Msgs, 0)
		require_Equal(t, state.FirstSeq, 1001)
		require_Equal(t, state.LastSeq, 1000)
		require_Equal(t, state.Consumers, 2)
		// Now check preAcks
		mset.mu.RLock()
		numPreAcks := len(mset.preAcks)
		mset.mu.RUnlock()
		require_Len(t, numPreAcks, 0)
	}
}

func TestNoRaceJetStreamClusterUnbalancedInterestMultipleFilteredConsumers(t *testing.T) {
	c, np := createStretchUnbalancedCluster(t)
	defer c.shutdown()
	defer np.stop()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	// Now create the stream.
	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "EVENTS",
		Subjects:  []string{"EV.>"},
		Replicas:  3,
		Retention: nats.InterestPolicy,
	})
	require_NoError(t, err)

	// Make sure it's leader is on S2.
	sl := c.servers[1]
	checkFor(t, 20*time.Second, 200*time.Millisecond, func() error {
		c.waitOnStreamLeader(globalAccountName, "EVENTS")
		if s := c.streamLeader(globalAccountName, "EVENTS"); s != sl {
			s.JetStreamStepdownStream(globalAccountName, "EVENTS")
			return fmt.Errorf("Server %s is not stream leader yet", sl)
		}
		return nil
	})

	// Create a fast ack consumer.
	_, err = js.Subscribe("EV.NEW", func(m *nats.Msg) {
		m.Ack()
	}, nats.Durable("C"), nats.ManualAck())
	require_NoError(t, err)

	// Make sure the consumer leader is on S3.
	cl := c.servers[2]
	checkFor(t, 20*time.Second, 200*time.Millisecond, func() error {
		c.waitOnConsumerLeader(globalAccountName, "EVENTS", "C")
		if s := c.consumerLeader(globalAccountName, "EVENTS", "C"); s != cl {
			s.JetStreamStepdownConsumer(globalAccountName, "EVENTS", "C")
			return fmt.Errorf("Server %s is not consumer leader yet", cl)
		}
		return nil
	})

	// Connect a client directly to the stream leader.
	nc, js = jsClientConnect(t, sl)
	defer nc.Close()

	// Now create another fast ack consumer.
	_, err = js.Subscribe("EV.UPDATED", func(m *nats.Msg) {
		m.Ack()
	}, nats.Durable("D"), nats.ManualAck())
	require_NoError(t, err)

	// Make sure this consumer leader is on S1.
	cl = c.servers[0]
	checkFor(t, 20*time.Second, 200*time.Millisecond, func() error {
		c.waitOnConsumerLeader(globalAccountName, "EVENTS", "D")
		if s := c.consumerLeader(globalAccountName, "EVENTS", "D"); s != cl {
			s.JetStreamStepdownConsumer(globalAccountName, "EVENTS", "D")
			return fmt.Errorf("Server %s is not consumer leader yet", cl)
		}
		return nil
	})

	numToSend := 500
	for i := 0; i < numToSend; i++ {
		_, err := js.PublishAsync("EV.NEW", nil)
		require_NoError(t, err)
		_, err = js.PublishAsync("EV.UPDATED", nil)
		require_NoError(t, err)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(20 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	// Let acks propagate.
	time.Sleep(250 * time.Millisecond)

	ci, err := js.ConsumerInfo("EVENTS", "D")
	require_NoError(t, err)
	require_Equal(t, ci.NumPending, 0)
	require_Equal(t, ci.NumAckPending, 0)
	require_Equal(t, ci.Delivered.Consumer, 500)
	require_Equal(t, ci.Delivered.Stream, 1000)
	require_Equal(t, ci.AckFloor.Consumer, 500)
	require_Equal(t, ci.AckFloor.Stream, 1000)

	// Check final stream state on all servers.
	for _, s := range c.servers {
		mset, err := s.GlobalAccount().lookupStream("EVENTS")
		require_NoError(t, err)
		state := mset.state()
		require_Equal(t, state.Msgs, 0)
		require_Equal(t, state.FirstSeq, 1001)
		require_Equal(t, state.LastSeq, 1000)
		require_Equal(t, state.Consumers, 2)
		// Now check preAcks
		mset.mu.RLock()
		numPreAcks := len(mset.preAcks)
		mset.mu.RUnlock()
		require_Len(t, numPreAcks, 0)
	}
}

func TestNoRaceParallelStreamAndConsumerCreation(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	// stream config.
	scfg := &StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo", "bar"},
		MaxMsgs:  10,
		Storage:  FileStorage,
		Replicas: 1,
	}

	// Will do these direct against the low level API to really make
	// sure parallel creation ok.
	np := 1000
	startCh := make(chan bool)
	errCh := make(chan error, np)
	wg := sync.WaitGroup{}
	wg.Add(np)

	var streams sync.Map

	for i := 0; i < np; i++ {
		go func() {
			defer wg.Done()

			// Make them all fire at once.
			<-startCh

			if mset, err := s.GlobalAccount().addStream(scfg); err != nil {
				t.Logf("Stream create got an error: %v", err)
				errCh <- err
			} else {
				streams.Store(mset, true)
			}
		}()
	}
	time.Sleep(100 * time.Millisecond)
	close(startCh)
	wg.Wait()

	// Check for no errors.
	if len(errCh) > 0 {
		t.Fatalf("Expected no errors, got %d: %v", len(errCh), <-errCh)
	}

	// Now make sure we really only created one stream.
	var numStreams int
	streams.Range(func(k, v any) bool {
		numStreams++
		return true
	})
	if numStreams > 1 {
		t.Fatalf("Expected only one stream to be really created, got %d out of %d attempts", numStreams, np)
	}

	// Also make sure we cleanup the inflight entries for streams.
	gacc := s.GlobalAccount()
	_, jsa, err := gacc.checkForJetStream()
	require_NoError(t, err)
	var numEntries int
	jsa.inflight.Range(func(k, v any) bool {
		numEntries++
		return true
	})
	if numEntries > 0 {
		t.Fatalf("Expected no inflight entries to be left over, got %d", numEntries)
	}

	// Now do consumers.
	mset, err := gacc.lookupStream("TEST")
	require_NoError(t, err)

	cfg := &ConsumerConfig{
		DeliverSubject: "to",
		Name:           "DLC",
		AckPolicy:      AckExplicit,
	}

	startCh = make(chan bool)
	errCh = make(chan error, np)
	wg.Add(np)

	var consumers sync.Map

	for i := 0; i < np; i++ {
		go func() {
			defer wg.Done()

			// Make them all fire at once.
			<-startCh

			if _, err = mset.addConsumer(cfg); err != nil {
				t.Logf("Consumer create got an error: %v", err)
				errCh <- err
			} else {
				consumers.Store(mset, true)
			}
		}()
	}
	time.Sleep(100 * time.Millisecond)
	close(startCh)
	wg.Wait()

	// Check for no errors.
	if len(errCh) > 0 {
		t.Fatalf("Expected no errors, got %d: %v", len(errCh), <-errCh)
	}

	// Now make sure we really only created one stream.
	var numConsumers int
	consumers.Range(func(k, v any) bool {
		numConsumers++
		return true
	})
	if numConsumers > 1 {
		t.Fatalf("Expected only one consumer to be really created, got %d out of %d attempts", numConsumers, np)
	}
}

func TestNoRaceRoutePool(t *testing.T) {
	var dur1 time.Duration
	var dur2 time.Duration

	total := 1_000_000

	for _, test := range []struct {
		name     string
		poolSize int
	}{
		{"no pooling", 0},
		{"pooling", 5},
	} {
		t.Run(test.name, func(t *testing.T) {
			tmpl := `
			port: -1
			accounts {
				A { users: [{user: "A", password: "A"}] }
				B { users: [{user: "B", password: "B"}] }
				C { users: [{user: "C", password: "C"}] }
				D { users: [{user: "D", password: "D"}] }
				E { users: [{user: "E", password: "E"}] }
			}
			cluster {
				port: -1
				name: "local"
				%s
				pool_size: %d
			}
		`
			conf1 := createConfFile(t, []byte(fmt.Sprintf(tmpl, _EMPTY_, test.poolSize)))
			s1, o1 := RunServerWithConfig(conf1)
			defer s1.Shutdown()

			conf2 := createConfFile(t, []byte(fmt.Sprintf(tmpl,
				fmt.Sprintf("routes: [\"nats://127.0.0.1:%d\"]", o1.Cluster.Port),
				test.poolSize)))
			s2, _ := RunServerWithConfig(conf2)
			defer s2.Shutdown()

			checkClusterFormed(t, s1, s2)

			wg := sync.WaitGroup{}
			wg.Add(5)

			sendAndRecv := func(acc string) (*nats.Conn, *nats.Conn) {
				t.Helper()

				s2nc := natsConnect(t, s2.ClientURL(), nats.UserInfo(acc, acc))
				count := 0
				natsSub(t, s2nc, "foo", func(_ *nats.Msg) {
					if count++; count == total {
						wg.Done()
					}
				})
				natsFlush(t, s2nc)

				s1nc := natsConnect(t, s1.ClientURL(), nats.UserInfo(acc, acc))

				checkSubInterest(t, s1, acc, "foo", time.Second)
				return s2nc, s1nc
			}

			var rcv = [5]*nats.Conn{}
			var snd = [5]*nats.Conn{}
			accs := []string{"A", "B", "C", "D", "E"}

			for i := 0; i < 5; i++ {
				rcv[i], snd[i] = sendAndRecv(accs[i])
				defer rcv[i].Close()
				defer snd[i].Close()
			}

			payload := []byte("some message")
			start := time.Now()
			for i := 0; i < 5; i++ {
				go func(idx int) {
					for i := 0; i < total; i++ {
						snd[idx].Publish("foo", payload)
					}
				}(i)
			}

			wg.Wait()
			dur := time.Since(start)
			if test.poolSize == 0 {
				dur1 = dur
			} else {
				dur2 = dur
			}
		})
	}
	perf1 := float64(total*5) / dur1.Seconds()
	t.Logf("No pooling: %.0f msgs/sec", perf1)
	perf2 := float64(total*5) / dur2.Seconds()
	t.Logf("Pooling   : %.0f msgs/sec", perf2)
	t.Logf("Gain      : %.2fx", perf2/perf1)
}

func testNoRaceRoutePerAccount(t *testing.T, useWildCard bool) {
	var dur1 time.Duration
	var dur2 time.Duration

	accounts := make([]string, 5)
	for i := 0; i < 5; i++ {
		akp, _ := nkeys.CreateAccount()
		pub, _ := akp.PublicKey()
		accounts[i] = pub
	}
	routeAccs := fmt.Sprintf("accounts: [\"%s\", \"%s\", \"%s\", \"%s\", \"%s\"]",
		accounts[0], accounts[1], accounts[2], accounts[3], accounts[4])

	total := 1_000_000

	for _, test := range []struct {
		name      string
		dedicated bool
	}{
		{"route for all accounts", false},
		{"route per account", true},
	} {
		t.Run(test.name, func(t *testing.T) {
			tmpl := `
			server_name: "%s"
			port: -1
			accounts {
				%s { users: [{user: "0", password: "0"}] }
				%s { users: [{user: "1", password: "1"}] }
				%s { users: [{user: "2", password: "2"}] }
				%s { users: [{user: "3", password: "3"}] }
				%s { users: [{user: "4", password: "4"}] }
			}
			cluster {
				port: -1
				name: "local"
				%s
				%s
			}
		`
			var racc string
			if test.dedicated {
				racc = routeAccs
			} else {
				racc = _EMPTY_
			}
			conf1 := createConfFile(t, []byte(fmt.Sprintf(tmpl, "A",
				accounts[0], accounts[1], accounts[2], accounts[3],
				accounts[4], _EMPTY_, racc)))
			s1, o1 := RunServerWithConfig(conf1)
			defer s1.Shutdown()

			conf2 := createConfFile(t, []byte(fmt.Sprintf(tmpl, "B",
				accounts[0], accounts[1], accounts[2], accounts[3], accounts[4],
				fmt.Sprintf("routes: [\"nats://127.0.0.1:%d\"]", o1.Cluster.Port),
				racc)))
			s2, _ := RunServerWithConfig(conf2)
			defer s2.Shutdown()

			checkClusterFormed(t, s1, s2)

			wg := sync.WaitGroup{}
			wg.Add(5)

			sendAndRecv := func(acc string, user string) (*nats.Conn, *nats.Conn) {
				t.Helper()

				s2nc := natsConnect(t, s2.ClientURL(), nats.UserInfo(user, user))
				count := 0
				var subj string
				var checkSubj string
				if useWildCard {
					subj, checkSubj = "foo.*", "foo.0"
				} else {
					subj, checkSubj = "foo", "foo"
				}
				natsSub(t, s2nc, subj, func(_ *nats.Msg) {
					if count++; count == total {
						wg.Done()
					}
				})
				natsFlush(t, s2nc)

				s1nc := natsConnect(t, s1.ClientURL(), nats.UserInfo(user, user))

				checkSubInterest(t, s1, acc, checkSubj, time.Second)
				return s2nc, s1nc
			}

			var rcv = [5]*nats.Conn{}
			var snd = [5]*nats.Conn{}
			users := []string{"0", "1", "2", "3", "4"}

			for i := 0; i < 5; i++ {
				rcv[i], snd[i] = sendAndRecv(accounts[i], users[i])
				defer rcv[i].Close()
				defer snd[i].Close()
			}

			payload := []byte("some message")
			start := time.Now()
			for i := 0; i < 5; i++ {
				go func(idx int) {
					for i := 0; i < total; i++ {
						var subj string
						if useWildCard {
							subj = fmt.Sprintf("foo.%d", i)
						} else {
							subj = "foo"
						}
						snd[idx].Publish(subj, payload)
					}
				}(i)
			}

			wg.Wait()
			dur := time.Since(start)
			if !test.dedicated {
				dur1 = dur
			} else {
				dur2 = dur
			}
		})
	}
	perf1 := float64(total*5) / dur1.Seconds()
	t.Logf("Route for all accounts: %.0f msgs/sec", perf1)
	perf2 := float64(total*5) / dur2.Seconds()
	t.Logf("Route per account     : %.0f msgs/sec", perf2)
	t.Logf("Gain                  : %.2fx", perf2/perf1)
}

func TestNoRaceRoutePerAccount(t *testing.T) {
	testNoRaceRoutePerAccount(t, false)
}

func TestNoRaceRoutePerAccountSubWithWildcard(t *testing.T) {
	testNoRaceRoutePerAccount(t, true)
}

// This test, which checks that messages are not duplicated when pooling or
// per-account routes are reloaded, would cause a DATA RACE that is not
// specific to the changes for pooling/per_account. For this reason, this
// test is located in the norace_test.go file.
func TestNoRaceRoutePoolAndPerAccountConfigReload(t *testing.T) {
	for _, test := range []struct {
		name           string
		poolSizeBefore string
		poolSizeAfter  string
		accountsBefore string
		accountsAfter  string
	}{
		{"from no pool to pool", _EMPTY_, "pool_size: 2", _EMPTY_, _EMPTY_},
		{"increase pool size", "pool_size: 2", "pool_size: 5", _EMPTY_, _EMPTY_},
		{"decrease pool size", "pool_size: 5", "pool_size: 2", _EMPTY_, _EMPTY_},
		{"from pool to no pool", "pool_size: 5", _EMPTY_, _EMPTY_, _EMPTY_},
		{"from no account to account", _EMPTY_, _EMPTY_, _EMPTY_, "accounts: [\"A\"]"},
		{"add account", _EMPTY_, _EMPTY_, "accounts: [\"B\"]", "accounts: [\"A\",\"B\"]"},
		{"remove account", _EMPTY_, _EMPTY_, "accounts: [\"A\",\"B\"]", "accounts: [\"B\"]"},
		{"from account to no account", _EMPTY_, _EMPTY_, "accounts: [\"A\"]", _EMPTY_},
		{"increase pool size and add account", "pool_size: 2", "pool_size: 3", "accounts: [\"B\"]", "accounts: [\"B\",\"A\"]"},
		{"decrease pool size and remove account", "pool_size: 3", "pool_size: 2", "accounts: [\"A\",\"B\"]", "accounts: [\"B\"]"},
	} {
		t.Run(test.name, func(t *testing.T) {
			tmplA := `
				port: -1
				server_name: "A"
				accounts {
					A { users: [{user: a, password: pwd}] }
					B { users: [{user: b, password: pwd}] }
				}
				cluster: {
					port: -1
					name: "local"
					%s
					%s
				}
			`
			confA := createConfFile(t, []byte(fmt.Sprintf(tmplA, test.poolSizeBefore, test.accountsBefore)))
			srva, optsA := RunServerWithConfig(confA)
			defer srva.Shutdown()

			tmplB := `
				port: -1
				server_name: "B"
				accounts {
					A { users: [{user: a, password: pwd}] }
					B { users: [{user: b, password: pwd}] }
				}
				cluster: {
					port: -1
					name: "local"
					%s
					%s
					routes: ["nats://127.0.0.1:%d"]
				}
			`
			confB := createConfFile(t, []byte(fmt.Sprintf(tmplB, test.poolSizeBefore, test.accountsBefore, optsA.Cluster.Port)))
			srvb, _ := RunServerWithConfig(confB)
			defer srvb.Shutdown()

			checkClusterFormed(t, srva, srvb)

			ncA := natsConnect(t, srva.ClientURL(), nats.UserInfo("a", "pwd"))
			defer ncA.Close()

			sub := natsSubSync(t, ncA, "foo")
			sub.SetPendingLimits(-1, -1)
			checkSubInterest(t, srvb, "A", "foo", time.Second)

			ncB := natsConnect(t, srvb.ClientURL(), nats.UserInfo("a", "pwd"))
			defer ncB.Close()

			wg := sync.WaitGroup{}
			wg.Add(1)
			ch := make(chan struct{})
			go func() {
				defer wg.Done()

				for i := 0; ; i++ {
					ncB.Publish("foo", []byte(fmt.Sprintf("%d", i)))
					select {
					case <-ch:
						return
					default:
					}
					if i%300 == 0 {
						time.Sleep(time.Duration(rand.Intn(5)) * time.Millisecond)
					}
				}
			}()

			var l *captureErrorLogger
			if test.accountsBefore != _EMPTY_ && test.accountsAfter == _EMPTY_ {
				l = &captureErrorLogger{errCh: make(chan string, 100)}
				srva.SetLogger(l, false, false)
			}

			time.Sleep(250 * time.Millisecond)
			reloadUpdateConfig(t, srva, confA, fmt.Sprintf(tmplA, test.poolSizeAfter, test.accountsAfter))
			time.Sleep(125 * time.Millisecond)
			reloadUpdateConfig(t, srvb, confB, fmt.Sprintf(tmplB, test.poolSizeAfter, test.accountsAfter, optsA.Cluster.Port))

			checkClusterFormed(t, srva, srvb)
			checkSubInterest(t, srvb, "A", "foo", time.Second)

			if l != nil {
				// Errors regarding "No route for account" should stop
				var ok bool
				for numErrs := 0; !ok && numErrs < 10; {
					select {
					case e := <-l.errCh:
						if strings.Contains(e, "No route for account") {
							numErrs++
						}
					case <-time.After(DEFAULT_ROUTE_RECONNECT + 250*time.Millisecond):
						ok = true
					}
				}
				if !ok {
					t.Fatalf("Still report of no route for account")
				}
			}

			close(ch)
			wg.Wait()

			for prev := -1; ; {
				msg, err := sub.NextMsg(50 * time.Millisecond)
				if err != nil {
					break
				}
				cur, _ := strconv.Atoi(string(msg.Data))
				if cur <= prev {
					t.Fatalf("Previous was %d, got %d", prev, cur)
				}
				prev = cur
			}
		})
	}
}

// This test ensures that outbound queues don't cause a run on
// memory when sending something to lots of clients.
func TestNoRaceClientOutboundQueueMemory(t *testing.T) {
	opts := DefaultOptions()
	s := RunServer(opts)
	defer s.Shutdown()

	var before runtime.MemStats
	var after runtime.MemStats

	var err error
	clients := make([]*nats.Conn, 50000)
	wait := &sync.WaitGroup{}
	wait.Add(len(clients))

	for i := 0; i < len(clients); i++ {
		clients[i], err = nats.Connect(fmt.Sprintf("nats://%s:%d", opts.Host, opts.Port), nats.InProcessServer(s))
		if err != nil {
			t.Fatalf("Error on connect: %v", err)
		}
		defer clients[i].Close()

		clients[i].Subscribe("test", func(m *nats.Msg) {
			wait.Done()
		})
	}

	runtime.GC()
	runtime.ReadMemStats(&before)

	nc, err := nats.Connect(fmt.Sprintf("nats://%s:%d", opts.Host, opts.Port), nats.InProcessServer(s))
	if err != nil {
		t.Fatalf("Error on connect: %v", err)
	}
	defer nc.Close()

	var m [48000]byte
	if err = nc.Publish("test", m[:]); err != nil {
		t.Fatal(err)
	}

	wait.Wait()

	runtime.GC()
	runtime.ReadMemStats(&after)

	hb, ha := float64(before.HeapAlloc), float64(after.HeapAlloc)
	ms := float64(len(m))
	diff := float64(ha) - float64(hb)
	inc := (diff / float64(hb)) * 100

	if inc > 10 {
		t.Logf("Message size:       %.1fKB\n", ms/1024)
		t.Logf("Subscribed clients: %d\n", len(clients))
		t.Logf("Heap allocs before: %.1fMB\n", hb/1024/1024)
		t.Logf("Heap allocs after:  %.1fMB\n", ha/1024/1024)
		t.Logf("Heap allocs delta:  %.1f%%\n", inc)

		t.Fatalf("memory increase was %.1f%% (should be <= 10%%)", inc)
	}
}

func TestNoRaceJetStreamClusterLeafnodeConnectPerf(t *testing.T) {
	// Uncomment to run. Needs to be on a big machine. Do not want as part of Travis tests atm.
	skip(t)

	tmpl := strings.Replace(jsClusterAccountsTempl, "store_dir:", "domain: cloud, store_dir:", 1)
	c := createJetStreamCluster(t, tmpl, "CLOUD", _EMPTY_, 3, 18033, true)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "STATE",
		Subjects: []string{"STATE.GLOBAL.CELL1.*.>"},
		Replicas: 3,
	})
	require_NoError(t, err)

	tmpl = strings.Replace(jsClusterTemplWithSingleFleetLeafNode, "store_dir:", "domain: vehicle, store_dir:", 1)

	var vinSerial int
	genVIN := func() string {
		vinSerial++
		return fmt.Sprintf("7PDSGAALXNN%06d", vinSerial)
	}

	numVehicles := 500
	for i := 0; i < numVehicles; i++ {
		start := time.Now()
		vin := genVIN()
		ln := c.createLeafNodeWithTemplateNoSystemWithProto(vin, tmpl, "ws")
		nc, js := jsClientConnect(t, ln)
		_, err := js.AddStream(&nats.StreamConfig{
			Name:     "VEHICLE",
			Subjects: []string{"STATE.GLOBAL.LOCAL.>"},
			Sources: []*nats.StreamSource{{
				Name:          "STATE",
				FilterSubject: fmt.Sprintf("STATE.GLOBAL.CELL1.%s.>", vin),
				External: &nats.ExternalStream{
					APIPrefix:     "$JS.cloud.API",
					DeliverPrefix: fmt.Sprintf("DELIVER.STATE.GLOBAL.CELL1.%s", vin),
				},
			}},
		})
		require_NoError(t, err)
		// Create the sourced stream.
		checkLeafNodeConnectedCount(t, ln, 1)
		if elapsed := time.Since(start); elapsed > 2*time.Second {
			t.Fatalf("Took too long to create leafnode %d connection: %v", i+1, elapsed)
		}
		nc.Close()
	}
}

func TestNoRaceJetStreamClusterDifferentRTTInterestBasedStreamPreAck(t *testing.T) {
	tmpl := `
	listen: 127.0.0.1:-1
	server_name: %s
	jetstream: {max_mem_store: 256MB, max_file_store: 2GB, store_dir: '%s'}

	cluster {
		name: "F3"
		listen: 127.0.0.1:%d
		routes = [%s]
	}

	accounts {
		$SYS { users = [ { user: "admin", pass: "s3cr3t!" } ] }
	}
	`

	//  Route Ports
	//	"S1": 14622,
	//	"S2": 15622,
	//	"S3": 16622,

	// S2 (stream leader) will have a slow path to S1 (via proxy) and S3 (consumer leader) will have a fast path.

	// Do these in order, S1, S2 (proxy) then S3.
	c := &cluster{t: t, servers: make([]*Server, 3), opts: make([]*Options, 3), name: "F3"}

	// S1
	// The route connection to S2 must be through a slow proxy
	np12 := createNetProxy(10*time.Millisecond, 1024*1024*1024, 1024*1024*1024, "route://127.0.0.1:15622", true)
	routes := fmt.Sprintf("%s, route://127.0.0.1:16622", np12.routeURL())
	conf := fmt.Sprintf(tmpl, "S1", t.TempDir(), 14622, routes)
	c.servers[0], c.opts[0] = RunServerWithConfig(createConfFile(t, []byte(conf)))

	// S2
	// The route connection to S1 must be through a slow proxy
	np21 := createNetProxy(10*time.Millisecond, 1024*1024*1024, 1024*1024*1024, "route://127.0.0.1:14622", true)
	routes = fmt.Sprintf("%s, route://127.0.0.1:16622", np21.routeURL())
	conf = fmt.Sprintf(tmpl, "S2", t.TempDir(), 15622, routes)
	c.servers[1], c.opts[1] = RunServerWithConfig(createConfFile(t, []byte(conf)))

	// S3
	conf = fmt.Sprintf(tmpl, "S3", t.TempDir(), 16622, "route://127.0.0.1:14622, route://127.0.0.1:15622")
	c.servers[2], c.opts[2] = RunServerWithConfig(createConfFile(t, []byte(conf)))

	c.checkClusterFormed()
	c.waitOnClusterReady()
	defer c.shutdown()
	defer np12.stop()
	defer np21.stop()

	slow := c.servers[0] // Expecting pre-acks here.
	sl := c.servers[1]   // Stream leader, will publish here.
	cl := c.servers[2]   // Consumer leader, will consume & ack here.

	snc, sjs := jsClientConnect(t, sl)
	defer snc.Close()

	cnc, cjs := jsClientConnect(t, cl)
	defer cnc.Close()

	// Now create the stream.
	_, err := sjs.AddStream(&nats.StreamConfig{
		Name:      "EVENTS",
		Subjects:  []string{"EV.>"},
		Replicas:  3,
		Retention: nats.InterestPolicy,
	})
	require_NoError(t, err)

	// Make sure it's leader is on S2.
	checkFor(t, 20*time.Second, 200*time.Millisecond, func() error {
		c.waitOnStreamLeader(globalAccountName, "EVENTS")
		if s := c.streamLeader(globalAccountName, "EVENTS"); s != sl {
			s.JetStreamStepdownStream(globalAccountName, "EVENTS")
			return fmt.Errorf("Server %s is not stream leader yet", sl)
		}
		return nil
	})

	// Now create the consumer.
	_, err = sjs.AddConsumer("EVENTS", &nats.ConsumerConfig{
		Durable:        "C",
		AckPolicy:      nats.AckExplicitPolicy,
		DeliverSubject: "dx",
	})
	require_NoError(t, err)

	// Make sure the consumer leader is on S3.
	checkFor(t, 20*time.Second, 200*time.Millisecond, func() error {
		c.waitOnConsumerLeader(globalAccountName, "EVENTS", "C")
		if s := c.consumerLeader(globalAccountName, "EVENTS", "C"); s != cl {
			s.JetStreamStepdownConsumer(globalAccountName, "EVENTS", "C")
			return fmt.Errorf("Server %s is not consumer leader yet", sl)
		}
		return nil
	})

	_, err = cjs.Subscribe(_EMPTY_, func(msg *nats.Msg) {
		msg.Ack()
	}, nats.BindStream("EVENTS"), nats.Durable("C"), nats.ManualAck())
	require_NoError(t, err)

	// Publish directly on the stream leader to make it efficient.
	for i := 0; i < 1_000; i++ {
		_, err := sjs.PublishAsync("EV.PAID", []byte("ok"))
		require_NoError(t, err)
	}
	select {
	case <-sjs.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	mset, err := slow.GlobalAccount().lookupStream("EVENTS")
	require_NoError(t, err)

	checkFor(t, 10*time.Second, 200*time.Millisecond, func() error {
		state := mset.state()
		if state.LastSeq != 1000 {
			return fmt.Errorf("Haven't received all messages yet (last seq %d)", state.LastSeq)
		}
		mset.mu.RLock()
		preAcks := mset.preAcks
		mset.mu.RUnlock()
		if preAcks == nil {
			return fmt.Errorf("Expected to have preAcks by now")
		}
		if state.Msgs == 0 {
			mset.mu.RLock()
			lp := len(mset.preAcks)
			mset.mu.RUnlock()
			if lp == 0 {
				return nil
			} else {
				t.Fatalf("Expected no preAcks with no msgs, but got %d", lp)
			}
		}
		return fmt.Errorf("Still have %d msgs left", state.Msgs)
	})

}

func TestNoRaceCheckAckFloorWithVeryLargeFirstSeqAndNewConsumers(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, _ := jsClientConnect(t, s)
	defer nc.Close()

	// Make sure to time bound here for the acksync call below.
	js, err := nc.JetStream(nats.MaxWait(200 * time.Millisecond))
	require_NoError(t, err)

	_, err = js.AddStream(&nats.StreamConfig{
		Name:      "TEST",
		Subjects:  []string{"wq-req"},
		Retention: nats.WorkQueuePolicy,
	})
	require_NoError(t, err)

	largeFirstSeq := uint64(1_200_000_000)
	err = js.PurgeStream("TEST", &nats.StreamPurgeRequest{Sequence: largeFirstSeq})
	require_NoError(t, err)
	si, err := js.StreamInfo("TEST")
	require_NoError(t, err)
	require_True(t, si.State.FirstSeq == largeFirstSeq)

	// Add a simple request to the stream.
	sendStreamMsg(t, nc, "wq-req", "HELP")

	sub, err := js.PullSubscribe("wq-req", "dlc")
	require_NoError(t, err)

	msgs, err := sub.Fetch(1)
	require_NoError(t, err)
	require_True(t, len(msgs) == 1)

	// The bug is around the checkAckFloor walking the sequences from current ackfloor
	// to the first sequence of the stream. We time bound the max wait with the js context
	// to 200ms. Since checkAckFloor is spinning and holding up processing of acks this will fail.
	// We will short circuit new consumers to fix this one.
	require_NoError(t, msgs[0].AckSync())

	// Now do again so we move past the new consumer with no ack floor situation.
	err = js.PurgeStream("TEST", &nats.StreamPurgeRequest{Sequence: 2 * largeFirstSeq})
	require_NoError(t, err)
	si, err = js.StreamInfo("TEST")
	require_NoError(t, err)
	require_True(t, si.State.FirstSeq == 2*largeFirstSeq)

	sendStreamMsg(t, nc, "wq-req", "MORE HELP")

	// We check this one directly for this use case.
	mset, err := s.GlobalAccount().lookupStream("TEST")
	require_NoError(t, err)
	o := mset.lookupConsumer("dlc")
	require_True(t, o != nil)

	// Purge will move the stream floor by default, so force into the situation where it is back to largeFirstSeq.
	// This will not trigger the new consumer logic, but will trigger a walk of the sequence space.
	// Fix will be to walk the lesser of the two linear spaces.
	o.mu.Lock()
	o.asflr = largeFirstSeq
	o.mu.Unlock()

	done := make(chan bool)
	go func() {
		o.checkAckFloor()
		done <- true
	}()

	select {
	case <-done:
		return
	case <-time.After(time.Second):
		t.Fatalf("Check ack floor taking too long!")
	}
}

func TestNoRaceReplicatedMirrorWithLargeStartingSequenceOverLeafnode(t *testing.T) {
	// Cluster B
	tmpl := strings.Replace(jsClusterTempl, "store_dir:", "domain: B, store_dir:", 1)
	c := createJetStreamCluster(t, tmpl, "B", _EMPTY_, 3, 22020, true)
	defer c.shutdown()

	// Cluster A
	// Domain is "A'
	lc := c.createLeafNodesWithStartPortAndDomain("A", 3, 22110, "A")
	defer lc.shutdown()

	lc.waitOnClusterReady()

	// Create a stream on B (HUB/CLOUD) and set its starting sequence very high.
	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo"},
		Replicas: 3,
	})
	require_NoError(t, err)

	err = js.PurgeStream("TEST", &nats.StreamPurgeRequest{Sequence: 1_000_000_000})
	require_NoError(t, err)

	// Send in a small amount of messages.
	for i := 0; i < 1000; i++ {
		sendStreamMsg(t, nc, "foo", "Hello")
	}

	si, err := js.StreamInfo("TEST")
	require_NoError(t, err)
	require_True(t, si.State.FirstSeq == 1_000_000_000)

	// Now try to create a replicated mirror on the leaf cluster.
	lnc, ljs := jsClientConnect(t, lc.randomServer())
	defer lnc.Close()

	_, err = ljs.AddStream(&nats.StreamConfig{
		Name: "TEST",
		Mirror: &nats.StreamSource{
			Name:   "TEST",
			Domain: "B",
		},
	})
	require_NoError(t, err)

	// Make sure we sync quickly.
	checkFor(t, time.Second, 200*time.Millisecond, func() error {
		si, err = ljs.StreamInfo("TEST")
		require_NoError(t, err)
		if si.State.Msgs == 1000 && si.State.FirstSeq == 1_000_000_000 {
			return nil
		}
		return fmt.Errorf("Mirror state not correct: %+v", si.State)
	})
}

func TestNoRaceBinaryStreamSnapshotEncodingBasic(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:              "TEST",
		Subjects:          []string{"*"},
		MaxMsgsPerSubject: 1,
	})
	require_NoError(t, err)

	// Set first key
	sendStreamMsg(t, nc, "key:1", "hello")

	// Set Second key but keep updating it, causing a laggard pattern.
	value := bytes.Repeat([]byte("Z"), 8*1024)

	for i := 0; i <= 1000; i++ {
		_, err := js.PublishAsync("key:2", value)
		require_NoError(t, err)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	// Now do more of swiss cheese style.
	for i := 3; i <= 1000; i++ {
		key := fmt.Sprintf("key:%d", i)
		_, err := js.PublishAsync(key, value)
		require_NoError(t, err)
		// Send it twice to create hole right behind it, like swiss cheese.
		_, err = js.PublishAsync(key, value)
		require_NoError(t, err)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	// Make for round numbers for stream state.
	sendStreamMsg(t, nc, "key:2", "hello")
	sendStreamMsg(t, nc, "key:2", "world")

	si, err := js.StreamInfo("TEST")
	require_NoError(t, err)
	require_True(t, si.State.FirstSeq == 1)
	require_True(t, si.State.LastSeq == 3000)
	require_True(t, si.State.Msgs == 1000)
	require_True(t, si.State.NumDeleted == 2000)

	mset, err := s.GlobalAccount().lookupStream("TEST")
	require_NoError(t, err)

	snap, err := mset.store.EncodedStreamState(0)
	require_NoError(t, err)

	// Now decode the snapshot.
	ss, err := DecodeStreamState(snap)
	require_NoError(t, err)

	require_Equal(t, ss.FirstSeq, 1)
	require_Equal(t, ss.LastSeq, 3000)
	require_Equal(t, ss.Msgs, 1000)
	require_Equal(t, ss.Deleted.NumDeleted(), 2000)
}

func TestNoRaceFilestoreBinaryStreamSnapshotEncodingLargeGaps(t *testing.T) {
	storeDir := t.TempDir()
	fcfg := FileStoreConfig{
		StoreDir:  storeDir,
		BlockSize: 512, // Small on purpose to create alot of blks.
	}
	fs, err := newFileStore(fcfg, StreamConfig{Name: "zzz", Subjects: []string{"zzz"}, Storage: FileStorage})
	require_NoError(t, err)
	defer fs.Stop()

	subj, msg := "zzz", bytes.Repeat([]byte("X"), 128)
	numMsgs := 20_000

	fs.StoreMsg(subj, nil, msg)
	for i := 2; i < numMsgs; i++ {
		seq, _, err := fs.StoreMsg(subj, nil, nil)
		require_NoError(t, err)
		fs.RemoveMsg(seq)
	}
	fs.StoreMsg(subj, nil, msg)

	snap, err := fs.EncodedStreamState(0)
	require_NoError(t, err)
	require_True(t, len(snap) < 512)

	// Now decode the snapshot.
	ss, err := DecodeStreamState(snap)
	require_NoError(t, err)

	require_True(t, ss.FirstSeq == 1)
	require_True(t, ss.LastSeq == 20_000)
	require_True(t, ss.Msgs == 2)
	require_True(t, len(ss.Deleted) <= 2)
	require_True(t, ss.Deleted.NumDeleted() == 19_998)
}

func TestNoRaceJetStreamClusterStreamSnapshotCatchup(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	// Client based API
	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:              "TEST",
		Subjects:          []string{"*"},
		MaxMsgsPerSubject: 1,
		Replicas:          3,
	})
	require_NoError(t, err)

	msg := []byte("Hello World")
	_, err = js.Publish("foo", msg)
	require_NoError(t, err)

	for i := 1; i < 1000; i++ {
		_, err := js.PublishAsync("bar", msg)
		require_NoError(t, err)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	sr := c.randomNonStreamLeader(globalAccountName, "TEST")
	sr.Shutdown()

	// In case we were connected to sr.
	nc, js = jsClientConnect(t, c.randomServer())
	defer nc.Close()

	// Now create a large gap.
	for i := 0; i < 50_000; i++ {
		_, err := js.PublishAsync("bar", msg)
		require_NoError(t, err)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(10 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	sl := c.streamLeader(globalAccountName, "TEST")
	sl.JetStreamSnapshotStream(globalAccountName, "TEST")

	sr = c.restartServer(sr)
	c.checkClusterFormed()
	c.waitOnServerCurrent(sr)
	c.waitOnStreamCurrent(sr, globalAccountName, "TEST")

	mset, err := sr.GlobalAccount().lookupStream("TEST")
	require_NoError(t, err)

	// Make sure it's caught up
	var state StreamState
	mset.store.FastState(&state)
	require_Equal(t, state.Msgs, 2)
	require_Equal(t, state.FirstSeq, 1)
	require_Equal(t, state.LastSeq, 51_000)
	require_Equal(t, state.NumDeleted, 51_000-2)

	sr.Shutdown()

	_, err = js.Publish("baz", msg)
	require_NoError(t, err)

	sl.JetStreamSnapshotStream(globalAccountName, "TEST")

	sr = c.restartServer(sr)
	c.checkClusterFormed()
	c.waitOnServerCurrent(sr)
	c.waitOnStreamCurrent(sr, globalAccountName, "TEST")

	mset, err = sr.GlobalAccount().lookupStream("TEST")
	require_NoError(t, err)
	mset.store.FastState(&state)

	require_Equal(t, state.Msgs, 3)
	require_Equal(t, state.FirstSeq, 1)
	require_Equal(t, state.LastSeq, 51_001)
	require_Equal(t, state.NumDeleted, 51_001-3)
}

func TestNoRaceStoreStreamEncoderDecoder(t *testing.T) {
	cfg := &StreamConfig{
		Name:       "zzz",
		Subjects:   []string{"*"},
		MaxMsgsPer: 1,
		Storage:    MemoryStorage,
	}
	ms, err := newMemStore(cfg)
	require_NoError(t, err)
	defer ms.Stop()

	fs, err := newFileStore(
		FileStoreConfig{StoreDir: t.TempDir()},
		StreamConfig{Name: "zzz", Subjects: []string{"*"}, MaxMsgsPer: 1, Storage: FileStorage},
	)
	require_NoError(t, err)
	defer fs.Stop()

	const seed = 2222222
	msg := bytes.Repeat([]byte("ABC"), 33) // ~100bytes

	maxEncodeTime := 2 * time.Second
	maxEncodeSize := 700 * 1024

	test := func(t *testing.T, gs StreamStore) {
		t.Parallel()
		prand := rand.New(rand.NewSource(seed))
		tick := time.NewTicker(time.Second)
		defer tick.Stop()
		done := time.NewTimer(10 * time.Second)

		for running := true; running; {
			select {
			case <-tick.C:
				var state StreamState
				gs.FastState(&state)
				if state.NumDeleted == 0 {
					continue
				}
				start := time.Now()
				snap, err := gs.EncodedStreamState(0)
				require_NoError(t, err)
				elapsed := time.Since(start)
				// Should take <1ms without race but if CI/CD is slow we will give it a bit of room.
				if elapsed > maxEncodeTime {
					t.Logf("Encode took longer then expected: %v", elapsed)
				}
				if len(snap) > maxEncodeSize {
					t.Fatalf("Expected snapshot size < %v got %v", friendlyBytes(maxEncodeSize), friendlyBytes(len(snap)))
				}
				ss, err := DecodeStreamState(snap)
				require_True(t, len(ss.Deleted) > 0)
				require_NoError(t, err)
			case <-done.C:
				running = false
			default:
				key := strconv.Itoa(prand.Intn(256_000))
				gs.StoreMsg(key, nil, msg)
			}
		}
	}

	for _, gs := range []StreamStore{ms, fs} {
		switch gs.(type) {
		case *memStore:
			t.Run("MemStore", func(t *testing.T) {
				test(t, gs)
			})
		case *fileStore:
			t.Run("FileStore", func(t *testing.T) {
				test(t, gs)
			})
		}
	}
}

func TestNoRaceJetStreamClusterKVWithServerKill(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	// Setup the KV bucket and use for making assertions.
	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()
	_, err := js.CreateKeyValue(&nats.KeyValueConfig{
		Bucket:   "TEST",
		Replicas: 3,
		History:  10,
	})
	require_NoError(t, err)

	// Total number of keys to range over.
	numKeys := 50

	// ID is the server id to explicitly connect to.
	work := func(ctx context.Context, wg *sync.WaitGroup, id int) {
		defer wg.Done()

		nc, js := jsClientConnectEx(t, c.servers[id], []nats.JSOpt{nats.Context(ctx)})
		defer nc.Close()

		kv, err := js.KeyValue("TEST")
		require_NoError(t, err)

		// 100 messages a second for each single client.
		tk := time.NewTicker(10 * time.Millisecond)
		defer tk.Stop()

		for {
			select {
			case <-ctx.Done():
				return

			case <-tk.C:
				// Pick a random key within the range.
				k := fmt.Sprintf("key.%d", rand.Intn(numKeys))
				// Attempt to get a key.
				e, err := kv.Get(k)
				// If found, attempt to update or delete.
				if err == nil {
					if rand.Intn(10) < 3 {
						kv.Delete(k, nats.LastRevision(e.Revision()))
					} else {
						kv.Update(k, nil, e.Revision())
					}
				} else if errors.Is(err, nats.ErrKeyNotFound) {
					kv.Create(k, nil)
				}
			}
		}
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	var wg sync.WaitGroup
	wg.Add(3)

	go work(ctx, &wg, 0)
	go work(ctx, &wg, 1)
	go work(ctx, &wg, 2)

	time.Sleep(time.Second)

	// Simulate server stop and restart.
	for i := 0; i < 7; i++ {
		s := c.randomServer()
		s.Shutdown()
		c.waitOnLeader()
		c.waitOnStreamLeader(globalAccountName, "KV_TEST")

		// Wait for a bit and then start the server again.
		time.Sleep(time.Duration(rand.Intn(1250)) * time.Millisecond)
		s = c.restartServer(s)
		c.waitOnServerCurrent(s)
		c.waitOnLeader()
		c.waitOnStreamLeader(globalAccountName, "KV_TEST")
		c.waitOnPeerCount(3)
	}

	// Stop the workload.
	cancel()
	wg.Wait()

	type fullState struct {
		state StreamState
		lseq  uint64
		clfs  uint64
	}

	grabState := func(mset *stream) *fullState {
		mset.mu.RLock()
		defer mset.mu.RUnlock()
		var state StreamState
		mset.store.FastState(&state)
		return &fullState{state, mset.lseq, mset.clfs}
	}

	grabStore := func(mset *stream) map[string][]uint64 {
		mset.mu.RLock()
		store := mset.store
		mset.mu.RUnlock()
		var state StreamState
		store.FastState(&state)
		storeMap := make(map[string][]uint64)
		for seq := state.FirstSeq; seq <= state.LastSeq; seq++ {
			if sm, err := store.LoadMsg(seq, nil); err == nil {
				storeMap[sm.subj] = append(storeMap[sm.subj], sm.seq)
			}
		}
		return storeMap
	}

	checkFor(t, 10*time.Second, 500*time.Millisecond, func() error {
		// Current stream leader.
		sl := c.streamLeader(globalAccountName, "KV_TEST")
		mset, err := sl.GlobalAccount().lookupStream("KV_TEST")
		require_NoError(t, err)
		lstate := grabState(mset)
		golden := grabStore(mset)

		// Report messages per server.
		for _, s := range c.servers {
			if s == sl {
				continue
			}
			mset, err := s.GlobalAccount().lookupStream("KV_TEST")
			require_NoError(t, err)
			state := grabState(mset)
			if !reflect.DeepEqual(state, lstate) {
				return fmt.Errorf("Expected follower state\n%+v\nto match leader's\n %+v", state, lstate)
			}
			sm := grabStore(mset)
			if !reflect.DeepEqual(sm, golden) {
				t.Fatalf("Expected follower store for %v\n%+v\nto match leader's %v\n %+v", s, sm, sl, golden)
			}
		}
		return nil
	})
}

func TestNoRaceFileStoreLargeMsgsAndFirstMatching(t *testing.T) {
	sd := t.TempDir()
	fs, err := newFileStore(
		FileStoreConfig{StoreDir: sd, BlockSize: 8 * 1024 * 1024},
		StreamConfig{Name: "zzz", Subjects: []string{">"}, Storage: FileStorage})
	require_NoError(t, err)
	defer fs.Stop()

	for i := 0; i < 150_000; i++ {
		fs.StoreMsg(fmt.Sprintf("foo.bar.%d", i), nil, nil)
	}
	for i := 0; i < 150_000; i++ {
		fs.StoreMsg(fmt.Sprintf("foo.baz.%d", i), nil, nil)
	}
	require_Equal(t, fs.numMsgBlocks(), 2)
	fs.mu.RLock()
	mb := fs.blks[1]
	fs.mu.RUnlock()
	fseq := atomic.LoadUint64(&mb.first.seq)
	// The -40 leaves enough mb.fss entries to kick in linear scan.
	for seq := fseq; seq < 300_000-40; seq++ {
		fs.RemoveMsg(uint64(seq))
	}
	start := time.Now()
	fs.LoadNextMsg("*.baz.*", true, fseq, nil)
	require_True(t, time.Since(start) < 200*time.Microsecond)
	// Now remove more to kick into non-linear logic.
	for seq := 300_000 - 40; seq < 300_000; seq++ {
		fs.RemoveMsg(uint64(seq))
	}
	start = time.Now()
	fs.LoadNextMsg("*.baz.*", true, fseq, nil)
	require_True(t, time.Since(start) < 200*time.Microsecond)
}

func TestNoRaceWSNoCorruptionWithFrameSizeLimit(t *testing.T) {
	testWSNoCorruptionWithFrameSizeLimit(t, 50000)
}

func TestNoRaceJetStreamAPIDispatchQueuePending(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	// Setup the KV bucket and use for making assertions.
	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo.*.*"},
	})
	require_NoError(t, err)

	// Queue up 500k messages all with different subjects.
	// We want to make num pending for a consumer expensive, so a large subject
	// space and wildcards for now does the trick.
	toks := []string{"foo", "bar", "baz"} // for second token.
	for i := 1; i <= 500_000; i++ {
		subj := fmt.Sprintf("foo.%s.%d", toks[rand.Intn(len(toks))], i)
		_, err := js.PublishAsync(subj, nil, nats.StallWait(time.Second))
		require_NoError(t, err)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(20 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	// To back up our pending queue we will create lots of filtered, with wildcards, R1 consumers
	// from a different server then the one hosting the stream.
	// ok to share this connection here.
	sldr := c.streamLeader(globalAccountName, "TEST")
	for _, s := range c.servers {
		if s != sldr {
			nc, js = jsClientConnect(t, s)
			defer nc.Close()
			break
		}
	}

	ngr, ncons := 100, 10
	startCh, errCh := make(chan bool), make(chan error, ngr)
	var wg, swg sync.WaitGroup
	wg.Add(ngr)
	swg.Add(ngr)

	// The wildcard in the filter subject is the key.
	cfg := &nats.ConsumerConfig{FilterSubject: "foo.*.22"}
	var tt atomic.Int64

	for i := 0; i < ngr; i++ {
		go func() {
			defer wg.Done()
			swg.Done()
			// Make them all fire at once.
			<-startCh

			for i := 0; i < ncons; i++ {
				start := time.Now()
				if _, err := js.AddConsumer("TEST", cfg); err != nil {
					errCh <- err
					t.Logf("Got err creating consumer: %v", err)
				}
				elapsed := time.Since(start)
				tt.Add(int64(elapsed))
			}
		}()
	}
	swg.Wait()
	close(startCh)
	time.Sleep(time.Millisecond)
	jsz, _ := sldr.Jsz(nil)
	// This could be 0 legit, so just log, don't fail.
	if jsz.JetStreamStats.API.Inflight == 0 {
		t.Log("Expected a non-zero inflight")
	}
	wg.Wait()

	if len(errCh) > 0 {
		t.Fatalf("Expected no errors, got %d: %v", len(errCh), <-errCh)
	}
}

func TestNoRaceJetStreamMirrorAndSourceConsumerFailBackoff(t *testing.T) {
	owt := srcConsumerWaitTime
	srcConsumerWaitTime = 2 * time.Second
	defer func() { srcConsumerWaitTime = owt }()

	// Check calculations first.
	for i := 1; i <= 20; i++ {
		backoff := calculateRetryBackoff(i)
		if i < 12 {
			require_Equal(t, backoff, time.Duration(i)*10*time.Second)
		} else {
			require_Equal(t, backoff, retryMaximum)
		}
	}

	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo.*.*"},
	})
	require_NoError(t, err)
	sl := c.streamLeader(globalAccountName, "TEST")

	// Create a mirror.
	ml := sl
	// Make sure not on the same server. Should not happened in general but possible.
	for ml == sl {
		js.DeleteStream("MIRROR")
		_, err = js.AddStream(&nats.StreamConfig{
			Name:   "MIRROR",
			Mirror: &nats.StreamSource{Name: "TEST"},
		})
		require_NoError(t, err)
		ml = c.streamLeader(globalAccountName, "MIRROR")
	}
	// Create a source.
	srcl := sl
	for srcl == sl {
		js.DeleteStream("SOURCE")
		_, err = js.AddStream(&nats.StreamConfig{
			Name:    "SOURCE",
			Sources: []*nats.StreamSource{{Name: "TEST"}},
		})
		require_NoError(t, err)
		srcl = c.streamLeader(globalAccountName, "MIRROR")
	}

	// Create sub to watch for the consumer create requests.
	nc, _ = jsClientConnect(t, ml)
	defer nc.Close()
	sub := natsSubSync(t, nc, "$JS.API.CONSUMER.CREATE.>")

	// Kill the server where the source is..
	sldr := c.streamLeader(globalAccountName, "TEST")
	sldr.Shutdown()

	// Wait for just greater than 5s. We should only see 1 request during this time.
	time.Sleep(6 * time.Second)
	// There should have been 2 requests, one for mirror, one for source
	n, _, _ := sub.Pending()
	require_Equal(t, n, 2)
	var mreq, sreq int
	for i := 0; i < 2; i++ {
		msg := natsNexMsg(t, sub, time.Second)
		if bytes.Contains(msg.Data, []byte("$JS.M.")) {
			mreq++
		} else if bytes.Contains(msg.Data, []byte("$JS.S.")) {
			sreq++
		}
	}
	if mreq != 1 || sreq != 1 {
		t.Fatalf("Consumer create captures invalid: mreq=%v sreq=%v", mreq, sreq)
	}

	// Now make sure that the fails is set properly.
	mset, err := c.streamLeader(globalAccountName, "MIRROR").GlobalAccount().lookupStream("MIRROR")
	require_NoError(t, err)
	mset.mu.RLock()
	fails := mset.mirror.fails
	mset.mu.RUnlock()
	require_Equal(t, fails, 1)

	mset, err = c.streamLeader(globalAccountName, "SOURCE").GlobalAccount().lookupStream("SOURCE")
	require_NoError(t, err)
	mset.mu.RLock()
	si := mset.sources["TEST > >"]
	mset.mu.RUnlock()
	require_True(t, si != nil)
	require_Equal(t, si.fails, 1)
}

func TestNoRaceJetStreamClusterStreamCatchupLargeInteriorDeletes(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	cfg := &nats.StreamConfig{
		Name:              "TEST",
		Subjects:          []string{"foo.*"},
		MaxMsgsPerSubject: 100,
		Replicas:          1,
	}

	_, err := js.AddStream(cfg)
	require_NoError(t, err)

	msg := bytes.Repeat([]byte("Z"), 2*1024)
	// We will create lots of interior deletes on our R1 then scale up.
	_, err = js.Publish("foo.0", msg)
	require_NoError(t, err)

	// Create 50k messages randomly from 1-100
	for i := 0; i < 50_000; i++ {
		subj := fmt.Sprintf("foo.%d", rand.Intn(100)+1)
		js.PublishAsync(subj, msg)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}
	// Now create a large gap.
	for i := 0; i < 100_000; i++ {
		js.PublishAsync("foo.2", msg)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}
	// Do 50k random again at end.
	for i := 0; i < 50_000; i++ {
		subj := fmt.Sprintf("foo.%d", rand.Intn(100)+1)
		js.PublishAsync(subj, msg)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	si, err := js.StreamInfo("TEST")
	require_NoError(t, err)

	cfg.Replicas = 2
	_, err = js.UpdateStream(cfg)
	require_NoError(t, err)

	// Let catchup start.
	c.waitOnStreamLeader(globalAccountName, "TEST")

	nl := c.randomNonStreamLeader(globalAccountName, "TEST")
	require_True(t, nl != nil)
	mset, err := nl.GlobalAccount().lookupStream("TEST")
	require_NoError(t, err)

	checkFor(t, 10*time.Second, 500*time.Millisecond, func() error {
		state := mset.state()
		if state.Msgs == si.State.Msgs {
			return nil
		}
		return fmt.Errorf("Msgs not equal %d vs %d", state.Msgs, si.State.Msgs)
	})
}

func TestNoRaceJetStreamClusterBadRestartsWithHealthzPolling(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	cfg := &nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo.>"},
		Replicas: 3,
	}
	_, err := js.AddStream(cfg)
	require_NoError(t, err)

	// We will poll healthz at a decent clip and make sure any restart logic works
	// correctly with assets coming and going.
	ch := make(chan struct{})
	defer close(ch)

	go func() {
		for {
			select {
			case <-ch:
				return
			case <-time.After(50 * time.Millisecond):
				for _, s := range c.servers {
					s.healthz(nil)
				}
			}
		}
	}()

	numConsumers := 500
	consumers := make([]string, 0, numConsumers)

	var wg sync.WaitGroup

	for i := 0; i < numConsumers; i++ {
		cname := fmt.Sprintf("CONS-%d", i+1)
		consumers = append(consumers, cname)
		wg.Add(1)
		go func() {
			defer wg.Done()
			_, err := js.PullSubscribe("foo.>", cname, nats.BindStream("TEST"))
			require_NoError(t, err)
		}()
	}
	wg.Wait()

	// Make sure all are reported.
	checkFor(t, 5*time.Second, 100*time.Millisecond, func() error {
		for _, s := range c.servers {
			jsz, _ := s.Jsz(nil)
			if jsz.Consumers != numConsumers {
				return fmt.Errorf("%v wrong number of consumers: %d vs %d", s, jsz.Consumers, numConsumers)
			}
		}
		return nil
	})

	// Now do same for streams.
	numStreams := 200
	streams := make([]string, 0, numStreams)

	for i := 0; i < numStreams; i++ {
		sname := fmt.Sprintf("TEST-%d", i+1)
		streams = append(streams, sname)
		wg.Add(1)
		go func() {
			defer wg.Done()
			_, err := js.AddStream(&nats.StreamConfig{Name: sname, Replicas: 3})
			require_NoError(t, err)
		}()
	}
	wg.Wait()

	// Make sure all are reported.
	checkFor(t, 5*time.Second, 100*time.Millisecond, func() error {
		for _, s := range c.servers {
			jsz, _ := s.Jsz(nil)
			if jsz.Streams != numStreams+1 {
				return fmt.Errorf("%v wrong number of streams: %d vs %d", s, jsz.Streams, numStreams+1)
			}
		}
		return nil
	})

	// Delete consumers.
	for _, cname := range consumers {
		err := js.DeleteConsumer("TEST", cname)
		require_NoError(t, err)
	}
	// Make sure reporting goes to zero.
	checkFor(t, 5*time.Second, 100*time.Millisecond, func() error {
		for _, s := range c.servers {
			jsz, _ := s.Jsz(nil)
			if jsz.Consumers != 0 {
				return fmt.Errorf("%v still has %d consumers", s, jsz.Consumers)
			}
		}
		return nil
	})

	// Delete streams
	for _, sname := range streams {
		err := js.DeleteStream(sname)
		require_NoError(t, err)
	}
	err = js.DeleteStream("TEST")
	require_NoError(t, err)

	// Make sure reporting goes to zero.
	checkFor(t, 5*time.Second, 100*time.Millisecond, func() error {
		for _, s := range c.servers {
			jsz, _ := s.Jsz(nil)
			if jsz.Streams != 0 {
				return fmt.Errorf("%v still has %d streams", s, jsz.Streams)
			}
		}
		return nil
	})
}

func TestNoRaceJetStreamKVReplaceWithServerRestart(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	nc, _ := jsClientConnect(t, c.randomServer())
	defer nc.Close()
	// Shorten wait time for disconnects.
	js, err := nc.JetStream(nats.MaxWait(time.Second))
	require_NoError(t, err)

	kv, err := js.CreateKeyValue(&nats.KeyValueConfig{
		Bucket:   "TEST",
		Replicas: 3,
	})
	require_NoError(t, err)

	createData := func(n int) []byte {
		const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
		b := make([]byte, n)
		for i := range b {
			b[i] = letterBytes[rand.Intn(len(letterBytes))]
		}
		return b
	}

	_, err = kv.Create("foo", createData(160))
	require_NoError(t, err)

	ch := make(chan struct{})
	wg := sync.WaitGroup{}

	// For counting errors that should not happen.
	errCh := make(chan error, 1024)

	wg.Add(1)
	go func() {
		defer wg.Done()

		var lastData []byte
		var revision uint64

		for {
			select {
			case <-ch:
				return
			default:
				k, err := kv.Get("foo")
				if err == nats.ErrKeyNotFound {
					errCh <- err
				} else if k != nil {
					if lastData != nil && k.Revision() == revision && !bytes.Equal(lastData, k.Value()) {
						errCh <- fmt.Errorf("data loss [%s][rev:%d] expected:[%q] is:[%q]\n", "foo", revision, lastData, k.Value())
					}
					newData := createData(160)
					if revision, err = kv.Update("foo", newData, k.Revision()); err == nil {
						lastData = newData
					}
				}
			}
		}
	}()

	// Wait a short bit.
	time.Sleep(2 * time.Second)
	for _, s := range c.servers {
		s.Shutdown()
		// Need to leave servers down for awhile to trigger bug properly.
		time.Sleep(5 * time.Second)
		s = c.restartServer(s)
		c.waitOnServerHealthz(s)
	}

	// Shutdown the go routine above.
	close(ch)
	// Wait for it to finish.
	wg.Wait()

	if len(errCh) != 0 {
		for err := range errCh {
			t.Logf("Received err %v during test", err)
		}
		t.Fatalf("Encountered errors")
	}
}

func TestNoRaceMemStoreCompactPerformance(t *testing.T) {
	//Load MemStore so that it is full
	subj, msg := "foo", make([]byte, 1000)
	storedMsgSize := memStoreMsgSize(subj, nil, msg)

	toStore := uint64(10_000)
	toStoreOnTop := uint64(1_000)
	setSeqNo := uint64(10_000_000_000)

	expectedPurge := toStore - 1
	maxBytes := storedMsgSize * toStore

	ms, err := newMemStore(&StreamConfig{Storage: MemoryStorage, MaxBytes: int64(maxBytes)})
	require_NoError(t, err)
	defer ms.Stop()

	for i := uint64(0); i < toStore; i++ {
		ms.StoreMsg(subj, nil, msg)
	}
	state := ms.State()
	require_Equal(t, toStore, state.Msgs)
	require_Equal(t, state.Bytes, storedMsgSize*toStore)

	//1st run: Load additional messages then compact
	for i := uint64(0); i < toStoreOnTop; i++ {
		ms.StoreMsg(subj, nil, msg)
	}
	startFirstRun := time.Now()
	purgedFirstRun, _ := ms.Compact(toStore + toStoreOnTop)
	elapsedFirstRun := time.Since(startFirstRun)
	require_Equal(t, expectedPurge, purgedFirstRun)

	//set the seq number to a very high value by compacting with a too high seq number
	purgedFull, _ := ms.Compact(setSeqNo)
	require_Equal(t, 1, purgedFull)

	//2nd run: Compact again
	for i := uint64(0); i < toStore; i++ {
		ms.StoreMsg(subj, nil, msg)
	}
	startSecondRun := time.Now()
	purgedSecondRun, _ := ms.Compact(setSeqNo + toStore - 1)
	elapsedSecondRun := time.Since(startSecondRun)
	require_Equal(t, expectedPurge, purgedSecondRun)

	//Calculate delta between runs and fail if it is too high
	require_LessThan(t, elapsedSecondRun-elapsedFirstRun, time.Duration(1)*time.Second)
}

func TestNoRaceJetStreamSnapshotsWithSlowAckDontSlowConsumer(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	ech := make(chan error)
	ecb := func(_ *nats.Conn, _ *nats.Subscription, err error) {
		if err != nil {
			ech <- err
		}
	}
	nc, js := jsClientConnect(t, s, nats.ErrorHandler(ecb))
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo"},
	})
	require_NoError(t, err)

	// Put in over 64MB.
	msg, toSend := make([]byte, 1024*1024), 80
	crand.Read(msg)

	for i := 0; i < toSend; i++ {
		_, err := js.Publish("foo", msg)
		require_NoError(t, err)
	}

	sreq := &JSApiStreamSnapshotRequest{
		DeliverSubject: nats.NewInbox(),
		ChunkSize:      1024 * 1024,
	}
	req, _ := json.Marshal(sreq)
	rmsg, err := nc.Request(fmt.Sprintf(JSApiStreamSnapshotT, "TEST"), req, time.Second)
	require_NoError(t, err)

	var resp JSApiStreamSnapshotResponse
	json.Unmarshal(rmsg.Data, &resp)
	require_True(t, resp.Error == nil)

	done := make(chan *nats.Msg)
	sub, _ := nc.Subscribe(sreq.DeliverSubject, func(m *nats.Msg) {
		// EOF
		if len(m.Data) == 0 {
			done <- m
			return
		}
	})
	defer sub.Unsubscribe()

	// Check that we do not get disconnected due to slow consumer.
	select {
	case msg := <-done:
		require_Equal(t, msg.Header.Get("Status"), "408")
		require_Equal(t, msg.Header.Get("Description"), "No Flow Response")
	case <-ech:
		t.Fatalf("Got disconnected: %v", err)
	case <-time.After(5 * time.Second):
		t.Fatalf("Should have received EOF with error status")
	}
}

func TestNoRaceJetStreamWQSkippedMsgsOnScaleUp(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	const pre = "CORE_ENT_DR_OTP_22."
	wcSubj := pre + ">"

	_, err := js.AddStream(&nats.StreamConfig{
		Name:        "TEST",
		Subjects:    []string{wcSubj},
		Retention:   nats.WorkQueuePolicy,
		AllowDirect: true,
		Replicas:    3,
	})
	require_NoError(t, err)

	cfg := &nats.ConsumerConfig{
		Durable:           "dlc",
		FilterSubject:     wcSubj,
		DeliverPolicy:     nats.DeliverAllPolicy,
		AckPolicy:         nats.AckExplicitPolicy,
		MaxAckPending:     10_000,
		AckWait:           500 * time.Millisecond,
		MaxWaiting:        100,
		MaxRequestExpires: 1050 * time.Millisecond,
	}
	_, err = js.AddConsumer("TEST", cfg)
	require_NoError(t, err)

	pdone := make(chan bool)
	cdone := make(chan bool)

	// We will have 51 consumer apps and a producer app. Make sure to wait for
	// all go routines to end at the end of the test.
	wg := sync.WaitGroup{}
	wg.Add(52)

	// Publish routine
	go func() {
		defer wg.Done()

		publishSubjects := []string{
			"CORE_ENT_DR_OTP_22.P.H.TC.10011.1010.918886682066",
			"CORE_ENT_DR_OTP_22.P.H.TC.10011.1010.918886682067",
			"CORE_ENT_DR_OTP_22.P.H.TC.10011.1010.916596543211",
			"CORE_ENT_DR_OTP_22.P.H.TC.10011.1010.916596543212",
			"CORE_ENT_DR_OTP_22.P.H.TC.10011.1010.916596543213",
			"CORE_ENT_DR_OTP_22.P.H.TC.10011.1010.916596543214",
			"CORE_ENT_DR_OTP_22.P.H.TC.10011.1010.916596543215",
			"CORE_ENT_DR_OTP_22.P.H.TC.10011.1010.916596543216",
			"CORE_ENT_DR_OTP_22.P.H.TC.10011.1010.916596543217",
		}
		// ~1.7kb
		msg := bytes.Repeat([]byte("Z"), 1750)

		// 200 msgs/s
		st := time.NewTicker(5 * time.Millisecond)
		defer st.Stop()

		nc, js := jsClientConnect(t, c.randomServer())
		defer nc.Close()

		for {
			select {
			case <-st.C:
				subj := publishSubjects[rand.Intn(len(publishSubjects))]
				_, err = js.Publish(subj, msg)
				require_NoError(t, err)
			case <-pdone:
				return
			}
		}
	}()

	consumerApp := func() {
		defer wg.Done()

		nc, js := jsClientConnect(t, c.randomServer())
		defer nc.Close()

		_, err := js.ConsumerInfo("TEST", "dlc")
		require_NoError(t, err)
		_, err = js.UpdateConsumer("TEST", cfg)
		require_NoError(t, err)

		sub, err := js.PullSubscribe(wcSubj, "dlc")
		require_NoError(t, err)

		st := time.NewTicker(100 * time.Millisecond)
		defer st.Stop()

		for {
			select {
			case <-st.C:
				msgs, err := sub.Fetch(1, nats.MaxWait(100*time.Millisecond))
				if err != nil {
					continue
				}
				require_Equal(t, len(msgs), 1)
				m := msgs[0]
				if rand.Intn(10) == 1 {
					m.Nak()
				} else {
					// Wait up to 20ms to ack.
					time.Sleep(time.Duration(rand.Intn(20)) * time.Millisecond)
					// This could fail and that is ok, system should recover due to low ack wait.
					m.Ack()
				}
			case <-cdone:
				return
			}
		}
	}

	// Now consumer side single.
	go consumerApp()

	// Wait for 2s
	time.Sleep(2 * time.Second)

	// Now spin up 50 more.
	for i := 1; i <= 50; i++ {
		if i%5 == 0 {
			time.Sleep(200 * time.Millisecond)
		}
		go consumerApp()
	}

	timeout := time.Now().Add(8 * time.Second)
	for time.Now().Before(timeout) {
		time.Sleep(750 * time.Millisecond)
		if s := c.consumerLeader(globalAccountName, "TEST", "dlc"); s != nil {
			s.JetStreamStepdownConsumer(globalAccountName, "TEST", "dlc")
		}
	}

	// Close publishers and defer closing consumers.
	close(pdone)
	defer func() {
		close(cdone)
		wg.Wait()
	}()

	checkFor(t, 30*time.Second, 50*time.Millisecond, func() error {
		si, err := js.StreamInfo("TEST")
		require_NoError(t, err)
		if si.State.NumDeleted > 0 || si.State.Msgs > 0 {
			return fmt.Errorf("State not correct: %+v", si.State)
		}
		return nil
	})
}

func TestNoRaceConnectionObjectReleased(t *testing.T) {
	ob1Conf := createConfFile(t, []byte(`
		listen: "127.0.0.1:-1"
		server_name: "B1"
		accounts {
			A { users: [{user: a, password: pwd}] }
			SYS { users: [{user: sys, password: pwd}] }
		}
		cluster {
			name: "B"
			listen: "127.0.0.1:-1"
		}
		gateway {
			name: "B"
			listen: "127.0.0.1:-1"
		}
		leaf {
			listen: "127.0.0.1:-1"
		}
		system_account: "SYS"
	`))
	sb1, ob1 := RunServerWithConfig(ob1Conf)
	defer sb1.Shutdown()

	oaConf := createConfFile(t, []byte(fmt.Sprintf(`
		listen: "127.0.0.1:-1"
		server_name: "A"
		accounts {
			A { users: [{user: a, password: pwd}] }
			SYS { users: [{user: sys, password: pwd}] }
		}
		gateway {
			name: "A"
			listen: "127.0.0.1:-1"
			gateways [
				{
					name: "B"
					url: "nats://a:[email protected]:%d"
				}
			]
		}
		websocket {
			listen: "127.0.0.1:-1"
			no_tls: true
		}
		system_account: "SYS"
	`, ob1.Gateway.Port)))
	sa, oa := RunServerWithConfig(oaConf)
	defer sa.Shutdown()

	waitForOutboundGateways(t, sa, 1, 2*time.Second)
	waitForOutboundGateways(t, sb1, 1, 2*time.Second)

	ob2Conf := createConfFile(t, []byte(fmt.Sprintf(`
		listen: "127.0.0.1:-1"
		server_name: "B2"
		accounts {
			A { users: [{user: a, password: pwd}] }
			SYS { users: [{user: sys, password: pwd}] }
		}
		cluster {
			name: "B"
			listen: "127.0.0.1:-1"
			routes: ["nats://127.0.0.1:%d"]
		}
		gateway {
			name: "B"
			listen: "127.0.0.1:-1"
		}
		system_account: "SYS"
	`, ob1.Cluster.Port)))
	sb2, _ := RunServerWithConfig(ob2Conf)
	defer sb2.Shutdown()

	checkClusterFormed(t, sb1, sb2)
	waitForOutboundGateways(t, sb2, 1, 2*time.Second)
	waitForInboundGateways(t, sa, 2, 2*time.Second)

	leafConf := createConfFile(t, []byte(fmt.Sprintf(`
		listen: "127.0.0.1:-1"
		server_name: "C"
		accounts {
			A { users: [{user: a, password: pwd}] }
			SYS { users: [{user: sys, password: pwd}] }
		}
		leafnodes {
			remotes [
				{ url: "nats://a:[email protected]:%d" }
			]
		}
		system_account: "SYS"
	`, ob1.LeafNode.Port)))
	leaf, _ := RunServerWithConfig(leafConf)
	defer leaf.Shutdown()

	checkLeafNodeConnected(t, leaf)

	// Start an independent MQTT server to check MQTT client connection.
	mo := testMQTTDefaultOptions()
	mo.ServerName = "MQTTServer"
	sm := testMQTTRunServer(t, mo)
	defer testMQTTShutdownServer(sm)

	mc, mr := testMQTTConnect(t, &mqttConnInfo{cleanSess: true}, mo.MQTT.Host, mo.MQTT.Port)
	defer mc.Close()
	testMQTTCheckConnAck(t, mr, mqttConnAckRCConnectionAccepted, false)

	nc := natsConnect(t, sb1.ClientURL(), nats.UserInfo("a", "pwd"))
	defer nc.Close()
	cid, err := nc.GetClientID()
	require_NoError(t, err)
	natsSubSync(t, nc, "foo")
	natsFlush(t, nc)

	ncWS := natsConnect(t, fmt.Sprintf("ws://a:[email protected]:%d", oa.Websocket.Port))
	defer ncWS.Close()
	cidWS, err := ncWS.GetClientID()
	require_NoError(t, err)

	var conns []net.Conn
	var total int
	var ch chan string

	track := func(c *client) {
		total++
		c.mu.Lock()
		conns = append(conns, c.nc)
		c.mu.Unlock()
		runtime.SetFinalizer(c, func(c *client) {
			ch <- fmt.Sprintf("Server=%s - Kind=%s - Conn=%v", c.srv, c.kindString(), c)
		})
	}
	// Track the connection for the MQTT client
	sm.mu.RLock()
	for _, c := range sm.clients {
		track(c)
	}
	sm.mu.RUnlock()

	// Track the connection from the NATS client
	track(sb1.getClient(cid))
	// The outbound connection to GW "A"
	track(sb1.getOutboundGatewayConnection("A"))
	// The inbound connection from GW "A"
	var inGW []*client
	sb1.getInboundGatewayConnections(&inGW)
	track(inGW[0])
	// The routes from sb2
	sb1.forEachRoute(func(r *client) {
		track(r)
	})
	// The leaf form "LEAF"
	sb1.mu.RLock()
	for _, l := range sb1.leafs {
		track(l)
	}
	sb1.mu.RUnlock()

	// Now from sb2, the routes to sb1
	sb2.forEachRoute(func(r *client) {
		track(r)
	})
	// The outbound connection to GW "A"
	track(sb2.getOutboundGatewayConnection("A"))

	// From server "A", track the outbound GW
	track(sa.getOutboundGatewayConnection("B"))
	inGW = inGW[:0]
	// Track the inbound GW connections
	sa.getInboundGatewayConnections(&inGW)
	for _, ig := range inGW {
		track(ig)
	}
	// Track the websocket client
	track(sa.getClient(cidWS))

	// From the LEAF server, the connection to sb1
	leaf.mu.RLock()
	for _, l := range leaf.leafs {
		track(l)
	}
	leaf.mu.RUnlock()

	// Now close all connections and wait to see if all connections
	// with the finalizer set is invoked.
	ch = make(chan string, total)
	// Close the clients and then all other connections to create a disconnect.
	nc.Close()
	mc.Close()
	ncWS.Close()
	for _, conn := range conns {
		conn.Close()
	}
	// Wait and see if we get them all.
	tm := time.NewTimer(10 * time.Second)
	defer tm.Stop()
	tk := time.NewTicker(10 * time.Millisecond)
	for clients := make([]string, 0, total); len(clients) < total; {
		select {
		case <-tk.C:
			runtime.GC()
		case cs := <-ch:
			clients = append(clients, cs)
		case <-tm.C:
			// Don't fail the test since there is no guarantee that
			// finalizers are invoked.
			t.Logf("Got %v out of %v finalizers", len(clients), total)
			slices.Sort(clients)
			for _, cs := range clients {
				t.Logf("  => %s", cs)
			}
			return
		}
	}
}

func TestNoRaceFileStoreMsgLoadNextMsgMultiPerf(t *testing.T) {
	fs, err := newFileStore(
		FileStoreConfig{StoreDir: t.TempDir()},
		StreamConfig{Name: "zzz", Subjects: []string{"foo.*"}, Storage: FileStorage})
	require_NoError(t, err)
	defer fs.Stop()

	// Put 1k msgs in
	for i := 0; i < 1000; i++ {
		subj := fmt.Sprintf("foo.%d", i)
		fs.StoreMsg(subj, nil, []byte("ZZZ"))
	}

	var smv StoreMsg

	// Now do normal load next with no filter.
	// This is baseline.
	start := time.Now()
	for i, seq := 0, uint64(1); i < 1000; i++ {
		sm, nseq, err := fs.LoadNextMsg(_EMPTY_, false, seq, &smv)
		require_NoError(t, err)
		require_True(t, sm.subj == fmt.Sprintf("foo.%d", i))
		require_Equal(t, nseq, seq)
		seq++
	}
	baseline := time.Since(start)
	t.Logf("Single - No filter %v", baseline)

	// Now do normal load next with wc filter.
	start = time.Now()
	for i, seq := 0, uint64(1); i < 1000; i++ {
		sm, nseq, err := fs.LoadNextMsg("foo.>", true, seq, &smv)
		require_NoError(t, err)
		require_True(t, sm.subj == fmt.Sprintf("foo.%d", i))
		require_Equal(t, nseq, seq)
		seq++
	}
	elapsed := time.Since(start)
	require_True(t, elapsed < 2*baseline)
	t.Logf("Single - WC filter %v", elapsed)

	// Now do multi load next with 1 wc entry.
	sl := NewSublistWithCache()
	sl.Insert(&subscription{subject: []byte("foo.>")})
	start = time.Now()
	for i, seq := 0, uint64(1); i < 1000; i++ {
		sm, nseq, err := fs.LoadNextMsgMulti(sl, seq, &smv)
		require_NoError(t, err)
		require_True(t, sm.subj == fmt.Sprintf("foo.%d", i))
		require_Equal(t, nseq, seq)
		seq++
	}
	elapsed = time.Since(start)
	require_True(t, elapsed < 2*baseline)
	t.Logf("Multi - Single WC filter %v", elapsed)

	// Now do multi load next with 1000 literal subjects.
	sl = NewSublistWithCache()
	for i := 0; i < 1000; i++ {
		subj := fmt.Sprintf("foo.%d", i)
		sl.Insert(&subscription{subject: []byte(subj)})
	}
	start = time.Now()
	for i, seq := 0, uint64(1); i < 1000; i++ {
		sm, nseq, err := fs.LoadNextMsgMulti(sl, seq, &smv)
		require_NoError(t, err)
		require_True(t, sm.subj == fmt.Sprintf("foo.%d", i))
		require_Equal(t, nseq, seq)
		seq++
	}
	elapsed = time.Since(start)
	require_True(t, elapsed < 2*baseline)
	t.Logf("Multi - 1000 filters %v", elapsed)
}

func TestNoRaceWQAndMultiSubjectFilters(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "TEST",
		Subjects:  []string{"Z.>"},
		Retention: nats.WorkQueuePolicy,
	})
	require_NoError(t, err)

	stopPubs := make(chan bool)

	publish := func(subject string) {
		nc, js := jsClientConnect(t, c.randomServer())
		defer nc.Close()

		for {
			select {
			case <-stopPubs:
				return
			default:
				_, _ = js.Publish(subject, []byte("hello"))
			}
		}
	}

	go publish("Z.foo")
	go publish("Z.bar")
	go publish("Z.baz")

	// Cancel pubs after 10s.
	time.AfterFunc(10*time.Second, func() { close(stopPubs) })

	// Create a consumer
	_, err = js.AddConsumer("TEST", &nats.ConsumerConfig{
		Durable:        "zzz",
		AckPolicy:      nats.AckExplicitPolicy,
		AckWait:        5 * time.Second,
		FilterSubjects: []string{"Z.foo", "Z.bar", "Z.baz"},
	})
	require_NoError(t, err)

	sub, err := js.PullSubscribe(_EMPTY_, "zzz", nats.Bind("TEST", "zzz"))
	require_NoError(t, err)

	received := make([]uint64, 0, 256_000)
	batchSize := 10

	for running := true; running; {
		msgs, err := sub.Fetch(batchSize, nats.MaxWait(2*time.Second))
		if err == nats.ErrTimeout {
			running = false
		}
		for _, m := range msgs {
			meta, err := m.Metadata()
			require_NoError(t, err)
			received = append(received, meta.Sequence.Stream)
			m.Ack()
		}
	}

	slices.Sort(received)

	var pseq, gaps uint64
	for _, seq := range received {
		if pseq != 0 && pseq != seq-1 {
			gaps += seq - pseq + 1
		}
		pseq = seq
	}
	si, err := js.StreamInfo("TEST")
	require_NoError(t, err)

	if si.State.Msgs != 0 || gaps > 0 {
		t.Fatalf("Orphaned msgs %d with %d gaps detected", si.State.Msgs, gaps)
	}
}

// https://github.com/nats-io/nats-server/issues/4957
func TestNoRaceWQAndMultiSubjectFiltersRace(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "TEST",
		Subjects:  []string{"Z.>"},
		Retention: nats.WorkQueuePolicy,
		Replicas:  1,
	})
	require_NoError(t, err)

	// The bug would happen when the stream was on same server as meta-leader.
	// So make that so.
	// Make sure stream leader is on S-1
	sl := c.streamLeader(globalAccountName, "TEST")
	checkFor(t, 5*time.Second, 100*time.Millisecond, func() error {
		if sl == c.leader() {
			return nil
		}
		// Move meta-leader since stream can be R1.
		snc, _ := jsClientConnect(t, c.randomServer(), nats.UserInfo("admin", "s3cr3t!"))
		defer snc.Close()
		if _, err := snc.Request(JSApiLeaderStepDown, nil, time.Second); err != nil {
			return err
		}
		return fmt.Errorf("stream leader on meta-leader")
	})

	start := make(chan struct{})
	var done, ready sync.WaitGroup

	// Create num go routines who will all race to create a consumer with the same filter subject but a different name.
	num := 10
	ready.Add(num)
	done.Add(num)

	for i := 0; i < num; i++ {
		go func(n int) {
			// Connect directly to the meta leader but with our own connection.
			s := c.leader()
			nc, js := jsClientConnect(t, s)
			defer nc.Close()

			ready.Done()
			defer done.Done()
			<-start

			js.AddConsumer("TEST", &nats.ConsumerConfig{
				Name:          fmt.Sprintf("C-%d", n),
				FilterSubject: "Z.foo",
				AckPolicy:     nats.AckExplicitPolicy,
			})
		}(i)
	}

	// Wait for requestors to be ready
	ready.Wait()
	close(start)
	done.Wait()

	checkFor(t, 5*time.Second, 100*time.Millisecond, func() error {
		si, err := js.StreamInfo("TEST")
		require_NoError(t, err)
		if si.State.Consumers != 1 {
			return fmt.Errorf("Consumer count not correct: %d vs 1", si.State.Consumers)
		}
		return nil
	})
}

func TestNoRaceFileStoreWriteFullStateUniqueSubjects(t *testing.T) {
	fcfg := FileStoreConfig{StoreDir: t.TempDir()}
	fs, err := newFileStore(fcfg,
		StreamConfig{Name: "zzz", Subjects: []string{"records.>"}, Storage: FileStorage, MaxMsgsPer: 1, MaxBytes: 15 * 1024 * 1024 * 1024})
	require_NoError(t, err)
	defer fs.Stop()

	qch := make(chan struct{})
	defer close(qch)

	go func() {
		const numThreshold = 1_000_000
		tick := time.NewTicker(1 * time.Second)
		for {
			select {
			case <-qch:
				return
			case <-tick.C:
				err := fs.writeFullState()
				var state StreamState
				fs.FastState(&state)
				if state.Msgs > numThreshold && err != nil {
					require_Error(t, err, errStateTooBig)
				}
			}
		}
	}()

	labels := []string{"AAAAA", "BBBB", "CCCC", "DD", "EEEEE"}
	msg := []byte(strings.Repeat("Z", 128))

	for i := 0; i < 100; i++ {
		partA := nuid.Next()
		for j := 0; j < 100; j++ {
			partB := nuid.Next()
			for k := 0; k < 500; k++ {
				partC := nuid.Next()
				partD := labels[rand.Intn(len(labels)-1)]
				subject := fmt.Sprintf("records.%s.%s.%s.%s.%s", partA, partB, partC, partD, nuid.Next())
				start := time.Now()
				fs.StoreMsg(subject, nil, msg)
				elapsed := time.Since(start)
				if elapsed > 500*time.Millisecond {
					t.Fatalf("Slow store for %q: %v\n", subject, elapsed)
				}
			}
		}
	}
	// Make sure we do write the full state on stop.
	fs.Stop()
	fi, err := os.Stat(filepath.Join(fcfg.StoreDir, msgDir, streamStreamStateFile))
	require_NoError(t, err)
	// ~500MB, could change if we tweak encodings..
	require_True(t, fi.Size() > 500*1024*1024)
}

// When a catchup takes a long time and the ingest rate is high enough to cause us
// to drop append entries and move our first past out catchup window due to max bytes or max msgs, etc.
func TestNoRaceLargeStreamCatchups(t *testing.T) {
	// This usually takes too long on Travis.
	t.Skip()

	var jsMaxOutTempl = `
	listen: 127.0.0.1:-1
	server_name: %s
	jetstream: {max_file_store: 22GB, store_dir: '%s', max_outstanding_catchup: 128KB}
	cluster {
		name: %s
		listen: 127.0.0.1:%d
		routes = [%s]
	}
	# For access to system account.
	accounts { $SYS { users = [ { user: "admin", pass: "s3cr3t!" } ] } }
`

	c := createJetStreamClusterWithTemplate(t, jsMaxOutTempl, "R3S", 3)
	defer c.shutdown()

	nc, _ := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	js, err := nc.JetStream(nats.PublishAsyncMaxPending(64 * 1024))
	require_NoError(t, err)

	cfg := &nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"Z.>"},
		MaxBytes: 4 * 1024 * 1024 * 1024,
		Replicas: 1, // Start at R1
	}

	_, err = js.AddStream(cfg)
	require_NoError(t, err)

	// Load up to a decent size first.
	num, msg := 25_000, bytes.Repeat([]byte("Z"), 256*1024)
	for i := 0; i < num; i++ {
		_, err := js.PublishAsync("Z.Z.Z", msg)
		require_NoError(t, err)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(20 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	var sl *Server
	time.AfterFunc(time.Second, func() {
		cfg.Replicas = 3
		_, err = js.UpdateStream(cfg)
		require_NoError(t, err)
		c.waitOnStreamLeader(globalAccountName, "TEST")
		sl = c.streamLeader(globalAccountName, "TEST")
	})

	// Run for 60 seconds sending new messages at a high rate.
	timeout := time.Now().Add(60 * time.Second)
	for time.Now().Before(timeout) {
		for i := 0; i < 5_000; i++ {
			// Not worried about each message, so not checking err here.
			// Just generating high load of new traffic while trying to catch up.
			js.PublishAsync("Z.Z.Z", msg)
		}
		// This will gate us waiting on a response.
		js.Publish("Z.Z.Z", msg)
	}

	// Make sure the leader has not changed.
	require_Equal(t, sl, c.streamLeader(globalAccountName, "TEST"))

	// Grab the leader and its state.
	mset, err := sl.GlobalAccount().lookupStream("TEST")
	require_NoError(t, err)
	expected := mset.state()

	checkFor(t, 45*time.Second, time.Second, func() error {
		for _, s := range c.servers {
			if s == sl {
				continue
			}
			mset, err := s.GlobalAccount().lookupStream("TEST")
			require_NoError(t, err)
			state := mset.state()
			if !reflect.DeepEqual(expected, state) {
				return fmt.Errorf("Follower %v state does not match: %+v vs %+v", s, state, expected)
			}
		}
		return nil
	})
}

func TestNoRaceLargeNumDeletesStreamCatchups(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	nc, _ := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	js, err := nc.JetStream(nats.PublishAsyncMaxPending(16 * 1024))
	require_NoError(t, err)

	cfg := &nats.StreamConfig{
		Name:     "TEST",
		Subjects: []string{"foo"},
		Replicas: 1, // Start at R1
	}
	_, err = js.AddStream(cfg)
	require_NoError(t, err)

	// We will manipulate the stream at the lower level to achieve large number of interior deletes.
	// We will store only 2 msgs, but have 100M deletes in between.
	sl := c.streamLeader(globalAccountName, "TEST")
	mset, err := sl.GlobalAccount().lookupStream("TEST")
	require_NoError(t, err)
	mset.mu.Lock()
	mset.store.StoreMsg("foo", nil, []byte("ok"))
	mset.store.SkipMsgs(2, 1_000_000_000)
	mset.store.StoreMsg("foo", nil, []byte("ok"))
	mset.store.SkipMsgs(1_000_000_003, 1_000_000_000)
	var state StreamState
	mset.store.FastState(&state)
	mset.lseq = state.LastSeq
	mset.mu.Unlock()

	cfg.Replicas = 3
	_, err = js.UpdateStream(cfg)
	require_NoError(t, err)
	c.waitOnStreamLeader(globalAccountName, "TEST")
	mset, err = sl.GlobalAccount().lookupStream("TEST")
	require_NoError(t, err)
	expected := mset.state()

	// This should happen fast and not spin on all interior deletes.
	checkFor(t, 250*time.Millisecond, 50*time.Millisecond, func() error {
		for _, s := range c.servers {
			if s == sl {
				continue
			}
			mset, err := s.GlobalAccount().lookupStream("TEST")
			require_NoError(t, err)
			state := mset.state()
			// Ignore LastTime for this test since we send delete range at end.
			state.LastTime = expected.LastTime
			if !reflect.DeepEqual(expected, state) {
				return fmt.Errorf("Follower %v state does not match: %+v vs %+v", s, state, expected)
			}
		}
		return nil
	})
}

func TestNoRaceJetStreamClusterMemoryStreamLastSequenceResetAfterRestart(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	numStreams := 250
	var wg sync.WaitGroup
	wg.Add(numStreams)

	for i := 1; i <= numStreams; i++ {
		go func(n int) {
			defer wg.Done()
			_, err := js.AddStream(&nats.StreamConfig{
				Name:     fmt.Sprintf("TEST:%d", n),
				Storage:  nats.MemoryStorage,
				Subjects: []string{fmt.Sprintf("foo.%d.*", n)},
				Replicas: 3,
			}, nats.MaxWait(30*time.Second))
			require_NoError(t, err)
			subj := fmt.Sprintf("foo.%d.bar", n)
			for i := 0; i < 222; i++ {
				js.Publish(subj, nil)
			}
		}(i)
	}
	wg.Wait()

	// Make sure all streams have a snapshot in place to stress the snapshot logic for memory based streams.
	for _, s := range c.servers {
		for i := 1; i <= numStreams; i++ {
			stream := fmt.Sprintf("TEST:%d", i)
			mset, err := s.GlobalAccount().lookupStream(stream)
			require_NoError(t, err)
			node := mset.raftNode()
			require_NotNil(t, node)
			node.InstallSnapshot(mset.stateSnapshot())
		}
	}

	// Do 5 rolling restarts waiting on healthz in between.
	for i := 0; i < 5; i++ {
		// Walk the servers and shut each down, and wipe the storage directory.
		for _, s := range c.servers {
			s.Shutdown()
			s.WaitForShutdown()
			s = c.restartServer(s)
			checkFor(t, 30*time.Second, time.Second, func() error {
				hs := s.healthz(nil)
				if hs.Error != _EMPTY_ {
					return errors.New(hs.Error)
				}
				return nil
			})
			// Make sure all streams are current after healthz returns ok.
			for i := 1; i <= numStreams; i++ {
				stream := fmt.Sprintf("TEST:%d", i)
				mset, err := s.GlobalAccount().lookupStream(stream)
				require_NoError(t, err)
				var state StreamState
				checkFor(t, 30*time.Second, time.Second, func() error {
					mset.store.FastState(&state)
					if state.LastSeq != 222 {
						return fmt.Errorf("%v Wrong last sequence %d for %q - State  %+v", s, state.LastSeq, stream, state)
					}
					return nil
				})
			}
		}
	}
}

func TestNoRaceJetStreamClusterMemoryWorkQueueLastSequenceResetAfterRestart(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3S", 3)
	defer c.shutdown()

	numStreams := 50
	var wg sync.WaitGroup
	wg.Add(numStreams)

	for i := 1; i <= numStreams; i++ {
		go func(n int) {
			defer wg.Done()

			nc, js := jsClientConnect(t, c.randomServer())
			defer nc.Close()

			checkFor(t, 5*time.Second, time.Second, func() error {
				_, err := js.AddStream(&nats.StreamConfig{
					Name:      fmt.Sprintf("TEST:%d", n),
					Storage:   nats.MemoryStorage,
					Retention: nats.WorkQueuePolicy,
					Subjects:  []string{fmt.Sprintf("foo.%d.*", n)},
					Replicas:  3,
				}, nats.MaxWait(time.Second))
				return err
			})

			subj := fmt.Sprintf("foo.%d.bar", n)
			for i := 0; i < 22; i++ {
				checkFor(t, 5*time.Second, time.Second, func() error {
					_, err := js.Publish(subj, nil)
					return err
				})
			}
			// Now consume them all as well.
			var err error
			var sub *nats.Subscription
			checkFor(t, 5*time.Second, time.Second, func() error {
				sub, err = js.PullSubscribe(subj, "wq")
				return err
			})

			var msgs []*nats.Msg
			checkFor(t, 5*time.Second, time.Second, func() error {
				msgs, err = sub.Fetch(22, nats.MaxWait(time.Second))
				return err
			})
			require_Equal(t, len(msgs), 22)
			for _, m := range msgs {
				checkFor(t, 5*time.Second, time.Second, func() error {
					return m.AckSync()
				})
			}
		}(i)
	}
	wg.Wait()

	// Do 2 rolling restarts waiting on healthz in between.
	for i := 0; i < 2; i++ {
		// Walk the servers and shut each down, and wipe the storage directory.
		for _, s := range c.servers {
			s.Shutdown()
			s.WaitForShutdown()
			s = c.restartServer(s)
			checkFor(t, 30*time.Second, time.Second, func() error {
				hs := s.healthz(nil)
				if hs.Error != _EMPTY_ {
					return errors.New(hs.Error)
				}
				return nil
			})
			// Make sure all streams are current after healthz returns ok.
			for i := 1; i <= numStreams; i++ {
				stream := fmt.Sprintf("TEST:%d", i)
				mset, err := s.GlobalAccount().lookupStream(stream)
				require_NoError(t, err)
				var state StreamState
				checkFor(t, 20*time.Second, time.Second, func() error {
					mset.store.FastState(&state)
					if state.LastSeq != 22 {
						return fmt.Errorf("%v Wrong last sequence %d for %q - State  %+v", s, state.LastSeq, stream, state)
					}
					if state.FirstSeq != 23 {
						return fmt.Errorf("%v Wrong first sequence %d for %q - State  %+v", s, state.FirstSeq, stream, state)
					}
					return nil
				})
			}
		}
	}
}

func TestNoRaceJetStreamClusterMirrorSkipSequencingBug(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R5S", 5)
	defer c.shutdown()

	nc, js := jsClientConnect(t, c.randomServer())
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:              "ORIGIN",
		Subjects:          []string{"foo.*"},
		MaxMsgsPerSubject: 1,
		Replicas:          1,
		Storage:           nats.MemoryStorage,
	})
	require_NoError(t, err)

	// Create a mirror with R5 such that it will be much slower than the ORIGIN.
	_, err = js.AddStream(&nats.StreamConfig{
		Name:     "M",
		Replicas: 5,
		Mirror:   &nats.StreamSource{Name: "ORIGIN"},
	})
	require_NoError(t, err)

	// Connect new directly to ORIGIN
	s := c.streamLeader(globalAccountName, "ORIGIN")
	nc, js = jsClientConnect(t, s)
	defer nc.Close()

	// We are going to send at a high rate and also delete some along the way
	// via the max msgs per limit.
	for i := 0; i < 500_000; i++ {
		subj := fmt.Sprintf("foo.%d", i)
		js.PublishAsync(subj, nil)
		// Create sequence holes every 100k.
		if i%100_000 == 0 {
			js.PublishAsync(subj, nil)
		}
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	checkFor(t, 20*time.Second, time.Second, func() error {
		si, err := js.StreamInfo("M")
		require_NoError(t, err)
		if si.State.Msgs != 500_000 {
			return fmt.Errorf("Expected 1M msgs, got state: %+v", si.State)
		}
		return nil
	})
}

func TestNoRaceJetStreamStandaloneDontReplyToAckBeforeProcessingIt(t *testing.T) {
	s := RunBasicJetStreamServer(t)
	defer s.Shutdown()

	// Client for API requests.
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:                 "WQ",
		Discard:              nats.DiscardNew,
		MaxMsgsPerSubject:    1,
		DiscardNewPerSubject: true,
		Retention:            nats.WorkQueuePolicy,
		Subjects:             []string{"queue.>"},
	})
	require_NoError(t, err)

	// Keep this low since we are going to run as many go routines
	// to consume, ack and republish the message.
	total := 10000
	// Populate the queue, one message per subject.
	for i := 0; i < total; i++ {
		js.Publish(fmt.Sprintf("queue.%d", i), []byte("hello"))
	}

	_, err = js.AddConsumer("WQ", &nats.ConsumerConfig{
		Durable:       "cons",
		AckPolicy:     nats.AckExplicitPolicy,
		MaxWaiting:    20000,
		MaxAckPending: -1,
	})
	require_NoError(t, err)

	sub, err := js.PullSubscribe("queue.>", "cons", nats.BindStream("WQ"))
	require_NoError(t, err)

	errCh := make(chan error, total)

	var wg sync.WaitGroup
	for iter := 0; iter < 3; iter++ {
		wg.Add(total)
		for i := 0; i < total; i++ {
			go func() {
				defer wg.Done()
				msgs, err := sub.Fetch(1)
				if err != nil {
					errCh <- err
					return
				}
				msg := msgs[0]
				err = msg.AckSync()
				if err != nil {
					errCh <- err
					return
				}
				_, err = js.Publish(msg.Subject, []byte("hello"))
				if err != nil {
					errCh <- err
					return
				}
			}()
		}
		wg.Wait()
		select {
		case err := <-errCh:
			t.Fatalf("Test failed, first error was: %v", err)
		default:
			// OK!
		}
	}
}

// Under certain scenarios an old index.db with a stream that has msg limits set will not restore properly
// due to an old index.db and compaction after the index.db took place which could lose per subject information.
func TestNoRaceFileStoreMsgLimitsAndOldRecoverState(t *testing.T) {
	for _, test := range []struct {
		name             string
		expectedFirstSeq uint64
		expectedLastSeq  uint64
		expectedMsgs     uint64
		transform        func(StreamConfig) StreamConfig
	}{
		{
			name:             "MaxMsgsPer",
			expectedFirstSeq: 10_001,
			expectedLastSeq:  1_010_001,
			expectedMsgs:     1_000_001,
			transform: func(config StreamConfig) StreamConfig {
				config.MaxMsgsPer = 1
				return config
			},
		},
		{
			name:             "MaxMsgs",
			expectedFirstSeq: 10_001,
			expectedLastSeq:  1_010_001,
			expectedMsgs:     1_000_001,
			transform: func(config StreamConfig) StreamConfig {
				config.MaxMsgs = 1_000_001
				return config
			},
		},
		{
			name:             "MaxBytes",
			expectedFirstSeq: 8_624,
			expectedLastSeq:  1_010_001,
			expectedMsgs:     1_001_378,
			transform: func(config StreamConfig) StreamConfig {
				config.MaxBytes = 1_065_353_216
				return config
			},
		},
	} {
		t.Run(test.name, func(t *testing.T) {
			sd := t.TempDir()
			fs, err := newFileStore(
				FileStoreConfig{StoreDir: sd},
				test.transform(StreamConfig{Name: "zzz", Subjects: []string{"foo.*"}, Storage: FileStorage}),
			)
			require_NoError(t, err)
			defer fs.Stop()

			msg := make([]byte, 1024)

			for i := 0; i < 10_000; i++ {
				subj := fmt.Sprintf("foo.%d", i)
				fs.StoreMsg(subj, nil, msg)
			}

			// This will write the index.db file. We will capture this and use it to replace a new one.
			sfile := filepath.Join(fs.fcfg.StoreDir, msgDir, streamStreamStateFile)
			fs.Stop()
			_, err = os.Stat(sfile)
			require_NoError(t, err)

			// Read it in and make sure len > 0.
			buf, err := os.ReadFile(sfile)
			require_NoError(t, err)
			require_True(t, len(buf) > 0)

			// Restart
			fs, err = newFileStore(
				FileStoreConfig{StoreDir: sd},
				test.transform(StreamConfig{Name: "zzz", Subjects: []string{"foo.*"}, Storage: FileStorage}),
			)
			require_NoError(t, err)
			defer fs.Stop()

			// Put in more messages with wider range. This will compact a bunch of the previous blocks.
			for i := 0; i < 1_000_001; i++ {
				subj := fmt.Sprintf("foo.%d", i)
				fs.StoreMsg(subj, nil, msg)
			}

			var ss StreamState
			fs.FastState(&ss)
			require_Equal(t, ss.FirstSeq, test.expectedFirstSeq)
			require_Equal(t, ss.LastSeq, test.expectedLastSeq)
			require_Equal(t, ss.Msgs, test.expectedMsgs)

			// Now stop again, but replace index.db with old one.
			fs.Stop()
			// Put back old stream state.
			require_NoError(t, os.WriteFile(sfile, buf, defaultFilePerms))

			// Restart
			fs, err = newFileStore(
				FileStoreConfig{StoreDir: sd},
				test.transform(StreamConfig{Name: "zzz", Subjects: []string{"foo.*"}, Storage: FileStorage}),
			)
			require_NoError(t, err)
			defer fs.Stop()

			fs.FastState(&ss)
			require_Equal(t, ss.FirstSeq, test.expectedFirstSeq)
			require_Equal(t, ss.LastSeq, test.expectedLastSeq)
			require_Equal(t, ss.Msgs, test.expectedMsgs)
		})
	}
}

func TestNoRaceJetStreamClusterCheckInterestStatePerformanceWQ(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3F", 3)
	defer c.shutdown()

	s := c.randomServer()
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "TEST",
		Subjects:  []string{"foo.*"},
		Retention: nats.WorkQueuePolicy,
	})
	require_NoError(t, err)

	// Load up a bunch of messages for three different subjects.
	msg := bytes.Repeat([]byte("Z"), 4096)
	for i := 0; i < 100_000; i++ {
		js.PublishAsync("foo.foo", msg)
	}
	for i := 0; i < 5_000; i++ {
		js.PublishAsync("foo.bar", msg)
		js.PublishAsync("foo.baz", msg)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}

	// We will not process this one and leave it as "offline".
	_, err = js.PullSubscribe("foo.foo", "A")
	require_NoError(t, err)
	subB, err := js.PullSubscribe("foo.bar", "B")
	require_NoError(t, err)
	subC, err := js.PullSubscribe("foo.baz", "C")
	require_NoError(t, err)

	// Now catch up both B and C but let A simulate being offline of very behind.
	for i := 0; i < 5; i++ {
		for _, sub := range []*nats.Subscription{subB, subC} {
			msgs, err := sub.Fetch(1000)
			require_NoError(t, err)
			require_Equal(t, len(msgs), 1000)
			for _, m := range msgs {
				m.Ack()
			}
		}
	}
	// Let acks process.
	nc.Flush()
	time.Sleep(200 * time.Millisecond)

	// Now test the check checkInterestState() on the stream.
	sl := c.streamLeader(globalAccountName, "TEST")
	mset, err := sl.GlobalAccount().lookupStream("TEST")
	require_NoError(t, err)

	expireAllBlks := func() {
		mset.mu.RLock()
		fs := mset.store.(*fileStore)
		mset.mu.RUnlock()
		fs.mu.RLock()
		for _, mb := range fs.blks {
			mb.tryForceExpireCache()
		}
		fs.mu.RUnlock()
	}

	// First expire all the blocks.
	expireAllBlks()

	start := time.Now()
	mset.checkInterestState()
	elapsed := time.Since(start)
	// This is actually ~300 microseconds but due to travis and race flags etc.
	// Was > 30 ms before fix for comparison, M2 macbook air.
	require_LessThan(t, elapsed, 5*time.Millisecond)

	// Make sure we set the chkflr correctly. The chkflr should be equal to asflr+1.
	// Otherwise, if chkflr would be set higher a subsequent call to checkInterestState will be ineffective.
	requireFloorsEqual := func(o *consumer) {
		t.Helper()
		require_True(t, o != nil)
		o.mu.RLock()
		defer o.mu.RUnlock()
		require_Equal(t, o.chkflr, o.asflr+1)
	}

	requireFloorsEqual(mset.lookupConsumer("A"))
	requireFloorsEqual(mset.lookupConsumer("B"))
	requireFloorsEqual(mset.lookupConsumer("C"))

	// Expire all the blocks again.
	expireAllBlks()

	// This checks the chkflr state.
	start = time.Now()
	mset.checkInterestState()
	elapsed = time.Since(start)
	require_LessThan(t, elapsed, 5*time.Millisecond)
}

func TestNoRaceJetStreamClusterCheckInterestStatePerformanceInterest(t *testing.T) {
	c := createJetStreamClusterExplicit(t, "R3F", 3)
	defer c.shutdown()

	s := c.randomServer()
	nc, js := jsClientConnect(t, s)
	defer nc.Close()

	_, err := js.AddStream(&nats.StreamConfig{
		Name:      "TEST",
		Subjects:  []string{"foo.*"},
		Retention: nats.InterestPolicy,
	})
	require_NoError(t, err)

	// We will not process this one and leave it as "offline".
	_, err = js.PullSubscribe("foo.foo", "A")
	require_NoError(t, err)
	_, err = js.PullSubscribe("foo.*", "B")
	require_NoError(t, err)
	// Make subC multi-subject.
	_, err = js.AddConsumer("TEST", &nats.ConsumerConfig{
		Durable:        "C",
		FilterSubjects: []string{"foo.foo", "foo.bar", "foo.baz"},
		AckPolicy:      nats.AckExplicitPolicy,
	})
	require_NoError(t, err)

	// Load up a bunch of messages for three different subjects.
	msg := bytes.Repeat([]byte("Z"), 4096)
	for i := 0; i < 90_000; i++ {
		js.PublishAsync("foo.foo", msg)
	}
	for i := 0; i < 5_000; i++ {
		js.PublishAsync("foo.bar", msg)
		js.PublishAsync("foo.baz", msg)
	}
	select {
	case <-js.PublishAsyncComplete():
	case <-time.After(5 * time.Second):
		t.Fatalf("Did not receive completion signal")
	}
	// This is so we do not asynchronously update our consumer state after we set the state due to notifications
	// from new messages for the stream.
	time.Sleep(250 * time.Millisecond)

	// Now catch up both B and C but let A simulate being offline of very behind.
	// Will do this manually here to speed up tests.
	sl := c.streamLeader(globalAccountName, "TEST")
	mset, err := sl.GlobalAccount().lookupStream("TEST")
	require_NoError(t, err)

	for _, cname := range []string{"B", "C"} {
		o := mset.lookupConsumer(cname)
		o.mu.Lock()
		o.setStoreState(&ConsumerState{
			Delivered: SequencePair{100_000, 100_000},
			AckFloor:  SequencePair{100_000, 100_000},
		})
		o.mu.Unlock()
	}

	// Now test the check checkInterestState() on the stream.
	start := time.Now()
	mset.checkInterestState()
	elapsed := time.Since(start)

	// Make sure we set the chkflr correctly.
	checkFloor := func(o *consumer) uint64 {
		require_True(t, o != nil)
		o.mu.RLock()
		defer o.mu.RUnlock()
		return o.chkflr
	}

	require_Equal(t, checkFloor(mset.lookupConsumer("A")), 1)
	require_Equal(t, checkFloor(mset.lookupConsumer("B")), 90_001)
	require_Equal(t, checkFloor(mset.lookupConsumer("C")), 100_001)

	// This checks the chkflr state. For this test this should be much faster,
	// two orders of magnitude then the first time.
	start = time.Now()
	mset.checkInterestState()
	require_True(t, time.Since(start) < elapsed/100)
}

func TestNoRaceJetStreamClusterLargeMetaSnapshotTiming(t *testing.T) {
	// This test was to show improvements in speed for marshaling the meta layer with lots of assets.
	// Move to S2.Encode vs EncodeBetter which is 2x faster and actually better compression.
	// Also moved to goccy json which is faster then the default and in my tests now always matches
	// the default encoder byte for byte which last time I checked it did not.
	t.Skip()

	c := createJetStreamClusterExplicit(t, "R3F", 3)
	defer c.shutdown()

	// Create 200 streams, each with 500 consumers.
	numStreams := 200
	numConsumers := 500
	wg := sync.WaitGroup{}
	wg.Add(numStreams)
	for i := 0; i < numStreams; i++ {
		go func() {
			defer wg.Done()
			s := c.randomServer()
			nc, js := jsClientConnect(t, s)
			defer nc.Close()
			sname := fmt.Sprintf("TEST-SNAPSHOT-%d", i)
			subj := fmt.Sprintf("foo.%d", i)
			_, err := js.AddStream(&nats.StreamConfig{
				Name:     sname,
				Subjects: []string{subj},
				Replicas: 3,
			})
			require_NoError(t, err)

			// Now consumers.
			for c := 0; c < numConsumers; c++ {
				_, err = js.AddConsumer(sname, &nats.ConsumerConfig{
					Durable:       fmt.Sprintf("C-%d", c),
					FilterSubject: subj,
					AckPolicy:     nats.AckExplicitPolicy,
					Replicas:      1,
				})
				require_NoError(t, err)
			}
		}()
	}
	wg.Wait()

	s := c.leader()
	js := s.getJetStream()
	n := js.getMetaGroup()
	// Now let's see how long it takes to create a meta snapshot and how big it is.
	start := time.Now()
	snap, err := js.metaSnapshot()
	require_NoError(t, err)
	require_NoError(t, n.InstallSnapshot(snap))
	t.Logf("Took %v to snap meta with size of %v\n", time.Since(start), friendlyBytes(len(snap)))
}

func TestNoRaceStoreReverseWalkWithDeletesPerf(t *testing.T) {
	cfg := StreamConfig{Name: "zzz", Subjects: []string{"foo.*"}, Storage: FileStorage}

	fs, err := newFileStore(FileStoreConfig{StoreDir: t.TempDir()}, cfg)
	require_NoError(t, err)
	defer fs.Stop()

	cfg.Storage = MemoryStorage
	ms, err := newMemStore(&cfg)
	require_NoError(t, err)
	defer ms.Stop()

	msg := []byte("Hello")

	for _, store := range []StreamStore{fs, ms} {
		store.StoreMsg("foo.A", nil, msg)
		for i := 0; i < 1_000_000; i++ {
			store.StoreMsg("foo.B", nil, msg)
		}
		store.StoreMsg("foo.C", nil, msg)

		var ss StreamState
		store.FastState(&ss)
		require_Equal(t, ss.Msgs, 1_000_002)

		// Create a bunch of interior deletes.
		p, err := store.PurgeEx("foo.B", 1, 0)
		require_NoError(t, err)
		require_Equal(t, p, 1_000_000)

		// Now simulate a walk backwards as we currently do when searching for starting sequence numbers in sourced streams.
		start := time.Now()
		var smv StoreMsg
		for seq := ss.LastSeq; seq > 0; seq-- {
			_, err := store.LoadMsg(seq, &smv)
			if err == errDeletedMsg || err == ErrStoreMsgNotFound {
				continue
			}
			require_NoError(t, err)
		}
		elapsed := time.Since(start)

		// Now use the optimized load prev.
		seq, seen := ss.LastSeq, 0
		start = time.Now()
		for {
			sm, err := store.LoadPrevMsg(seq, &smv)
			if err == ErrStoreEOF {
				break
			}
			require_NoError(t, err)
			seq = sm.seq - 1
			seen++
		}
		elapsedNew := time.Since(start)
		require_Equal(t, seen, 2)

		switch store.(type) {
		case *memStore:
			require_True(t, elapsedNew < elapsed)
		case *fileStore:
			// Bigger gains for filestore, 10x
			require_True(t, elapsedNew*10 < elapsed)
		}
	}
}

type fastProdLogger struct {
	DummyLogger
	gotIt chan struct{}
}

func (l *fastProdLogger) Debugf(format string, args ...any) {
	msg := fmt.Sprintf(format, args...)
	if strings.Contains(msg, "fast producer") {
		select {
		case l.gotIt <- struct{}{}:
		default:
		}
	}
}

type slowWriteConn struct {
	sync.RWMutex
	net.Conn
	delay bool
}

func (c *slowWriteConn) Write(b []byte) (int, error) {
	c.RLock()
	delay := c.delay
	c.RUnlock()
	if delay {
		time.Sleep(100 * time.Millisecond)
	}
	return c.Conn.Write(b)
}

func TestNoRaceNoFastProducerStall(t *testing.T) {
	tmpl := `
		listen: "127.0.0.1:-1"
		no_fast_producer_stall: %s
	`
	conf := createConfFile(t, []byte(fmt.Sprintf(tmpl, "true")))
	s, _ := RunServerWithConfig(conf)
	defer s.Shutdown()

	l := &fastProdLogger{gotIt: make(chan struct{}, 1)}
	s.SetLogger(l, true, false)

	ncSlow := natsConnect(t, s.ClientURL(), nats.ReconnectWait(10*time.Millisecond))
	defer ncSlow.Close()
	natsSub(t, ncSlow, "foo", func(_ *nats.Msg) {})
	natsFlush(t, ncSlow)

	cid, err := ncSlow.GetClientID()
	require_NoError(t, err)
	c := s.GetClient(cid)
	require_True(t, c != nil)

	c.mu.Lock()
	swc := &slowWriteConn{Conn: c.nc, delay: true}
	c.nc = swc
	c.mu.Unlock()

	defer func() {
		swc.Lock()
		swc.delay = false
		swc.Unlock()
	}()

	// The producer could still overwhelm the "fast" consumer.
	// So we will send more than what it will use as a target
	// to consider the test done.
	total := 2_000_000
	target := total / 2
	ch := make(chan struct{}, 1)
	var count int

	ncFast := natsConnect(t, s.ClientURL(), nats.ReconnectWait(10*time.Millisecond))
	defer ncFast.Close()
	fastSub := natsSub(t, ncFast, "foo", func(_ *nats.Msg) {
		if count++; count == target {
			ch <- struct{}{}
		}
	})
	err = fastSub.SetPendingLimits(-1, -1)
	require_NoError(t, err)
	natsFlush(t, ncFast)

	ncProd := natsConnect(t, s.ClientURL(), nats.ReconnectWait(10*time.Millisecond))
	defer ncProd.Close()

	cid, err = ncProd.GetClientID()
	require_NoError(t, err)
	pc := s.GetClient(cid)
	pc.mu.Lock()
	pcnc := pc.nc
	pc.mu.Unlock()

	payload := make([]byte, 256)

	for i := 0; i < total; i++ {
		natsPub(t, ncProd, "foo", payload)
	}
	select {
	case <-ch:
		// OK
	case <-time.After(10 * time.Second):
		t.Fatal("Test timed-out")
	}
	// Now wait a bit and make sure we did not get any fast producer debug statements.
	select {
	case <-l.gotIt:
		t.Fatal("Got debug logs about fast producer")
	case <-time.After(time.Second):
		// OK
	}

	// We don't need that one anymore
	ncFast.Close()
	// Now we will conf reload to enable fast producer stalling.
	reloadUpdateConfig(t, s, conf, fmt.Sprintf(tmpl, "false"))

	// Since the producer can block, we will publish from a different routine,
	// and check for the debug trace from the main.
	wg := sync.WaitGroup{}
	wg.Add(1)
	doneCh := make(chan struct{})
	go func() {
		defer wg.Done()
		for i := 0; ; i++ {
			ncProd.Publish("foo", payload)
			select {
			case <-doneCh:
				return
			default:
			}
			if i%1000 == 0 {
				time.Sleep(time.Millisecond)
			}
		}
	}()
	select {
	case <-l.gotIt:
		pcnc.Close()
		close(doneCh)
	case <-time.After(20 * time.Second):
		t.Fatal("Timed-out waiting for a warning")
	}
	wg.Wait()
}

func TestNoRaceProducerStallLimits(t *testing.T) {
	tmpl := `
		listen: "127.0.0.1:-1"
	`
	conf := createConfFile(t, []byte(tmpl))
	s, _ := RunServerWithConfig(conf)
	defer s.Shutdown()

	ncSlow := natsConnect(t, s.ClientURL())
	defer ncSlow.Close()
	natsSub(t, ncSlow, "foo", func(m *nats.Msg) { m.Respond([]byte("42")) })
	natsFlush(t, ncSlow)

	ncProd := natsConnect(t, s.ClientURL())
	defer ncProd.Close()

	cid, err := ncSlow.GetClientID()
	require_NoError(t, err)
	c := s.GetClient(cid)
	require_True(t, c != nil)

	// Artificially set a stall channel on the subscriber.
	c.mu.Lock()
	c.out.stc = make(chan struct{})
	c.mu.Unlock()

	start := time.Now()
	_, err = ncProd.Request("foo", []byte("HELLO"), time.Second)
	elapsed := time.Since(start)
	require_NoError(t, err)

	// This should have not cleared on its own but should have bettwen min and max pause.
	require_True(t, elapsed >= stallClientMinDuration)
	require_True(t, elapsed < stallClientMaxDuration)

	// Now test total maximum by loading up a bunch of requests and measuring the last one.
	// Artificially set a stall channel again on the subscriber.
	c.mu.Lock()
	c.out.stc = make(chan struct{})
	// This will prevent us from clearing the stc.
	c.out.pb = c.out.mp/4*3 + 100
	c.mu.Unlock()

	for i := 0; i < 10; i++ {
		err = ncProd.PublishRequest("foo", "bar", []byte("HELLO"))
		require_NoError(t, err)
	}
	start = time.Now()
	_, err = ncProd.Request("foo", []byte("HELLO"), time.Second)
	elapsed = time.Since(start)
	require_NoError(t, err)

	require_True(t, elapsed >= stallTotalAllowed)
	// Should always be close to totalAllowed (e.g. 10ms), but if you run alot of them in one go can bump up
	// just past 12ms, hence the Max setting below to avoid a flapper.
	require_True(t, elapsed < stallTotalAllowed+stallClientMaxDuration)
}

func TestNoRaceFileStorePurgeExAsyncTombstones(t *testing.T) {
	fs, err := newFileStore(
		FileStoreConfig{StoreDir: t.TempDir()},
		StreamConfig{Name: "zzz", Subjects: []string{"*.*"}, Storage: FileStorage})
	require_NoError(t, err)
	defer fs.Stop()

	msg := []byte("zzz")

	fs.StoreMsg("foo.A", nil, msg)
	fs.StoreMsg("foo.B", nil, msg)
	for i := 0; i < 500; i++ {
		fs.StoreMsg("foo.C", nil, msg)
	}
	fs.StoreMsg("foo.D", nil, msg)

	// Load all blocks to avoid that being a factor in timing.
	fs.mu.RLock()
	for _, mb := range fs.blks {
		mb.loadMsgs()
	}
	fs.mu.RUnlock()

	// Now purge 1 that is not the first message and take note of time.
	// Since we are loaded this should mostly be the time to write / flush tombstones.
	start := time.Now()
	n, err := fs.PurgeEx("foo.B", 0, 0)
	elapsed := time.Since(start)
	require_NoError(t, err)
	require_Equal(t, n, 1)

	start = time.Now()
	n, err = fs.PurgeEx("foo.C", 0, 0)
	elapsed2 := time.Since(start)
	require_NoError(t, err)
	require_Equal(t, n, 500)

	// If we are flushing for each tombstone the second elapsed time will be a larger multiple of the single message purge.
	// In testing this is like >200x
	// With async and flush for all tombstones will be ~30x
	require_True(t, elapsed*50 > elapsed2)
}