Files
Tim Deeb-SwihartandGitHub be7b5514a5 Reconnect to SQL databases when connections fail (#5926)
## What changed?

Both our PostgreSQL and MySQL database backends will now automatically
reconnect to the database when certain errors occur: all errors chosen
have been experienced when testing this behavior through an AWS Aurora
RDS failover of either MySQL or PostgreSQL.

For both backends we will reconnect when we see:
- `ECONNRESET`
- `ECONNABORTED`
- `ECONNREFUSED`
- `io.EOF`
- `io.ErrUnexpectedEOF`
- `database/sql/driver.ErrBadConn`

for postgres we will also reconnect on the following SQLStates:
- `25006` read-only transaction
- `57P03` cannot connect now
- `0A000` feature not supported, but ONLY when the message is `cannot
set transaction read-write mode during recovery`

for mysql we will also reconnect when we see the following error codes:
- `1040` too many connections 
- `1792` read-only transaction (SQLstate `25006`)
- `1836` running in read-only mode

This logic is easily extensible should we discover more failure modes
over time

## Why?

We've had multiple community reports of Temporal problems during RDS
failover. One part of this is the fact that we wouldn't necessarily
reconnect; we were at the whims of our chosen SQL abstraction's
connection pooling logic.

## How did you test it?

I manually tested this functionality in the presence of repeated RDS
failovers: 

- [x] postgres12 plugin with pq driver
- [x] postgres12 plugin with pgx driver
- [x] mysql plugin

Automated testing will be added to our regular testing pipelines once
our infrastructure friends have added the support I need (it's in
progress)

## Potential risks

We're concerned there's a correctness issue in our PostgreSQL backend
that's related to our behavior during an RDS failover. If we merge this
before I figure out what's going on, we could hide the issue and make it
harder to reproduce.

## Documentation
N/A

## Is hotfix candidate?
Yes?
2024-05-17 16:59:15 -07:00

242 lines
6.4 KiB
Go

// The MIT License
//
// Copyright (c) 2020 Temporal Technologies Inc. All rights reserved.
//
// Copyright (c) 2020 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package tests
import (
"math/rand"
"testing"
"github.com/stretchr/testify/require"
"github.com/stretchr/testify/suite"
"go.temporal.io/server/common/persistence/sql/sqlplugin"
"go.temporal.io/server/common/shuffle"
)
type (
historyShardSuite struct {
suite.Suite
*require.Assertions
store sqlplugin.DB
}
)
const (
testHistoryShardEncoding = "random encoding"
)
var (
testHistoryShardData = []byte("random history shard data")
)
func NewHistoryShardSuite(
t *testing.T,
store sqlplugin.DB,
) *historyShardSuite {
return &historyShardSuite{
Assertions: require.New(t),
store: store,
}
}
func (s *historyShardSuite) SetupSuite() {
}
func (s *historyShardSuite) TearDownSuite() {
}
func (s *historyShardSuite) SetupTest() {
s.Assertions = require.New(s.T())
}
func (s *historyShardSuite) TearDownTest() {
}
func (s *historyShardSuite) TestInsert_Success() {
shardID := rand.Int31()
rangeID := int64(1)
shard := s.newRandomShardRow(shardID, rangeID)
result, err := s.store.InsertIntoShards(newExecutionContext(), &shard)
s.NoError(err)
rowsAffected, err := result.RowsAffected()
s.NoError(err)
s.Equal(1, int(rowsAffected))
}
func (s *historyShardSuite) TestInsert_Fail_Duplicate() {
shardID := rand.Int31()
rangeID := int64(1)
shard := s.newRandomShardRow(shardID, rangeID)
result, err := s.store.InsertIntoShards(newExecutionContext(), &shard)
s.NoError(err)
rowsAffected, err := result.RowsAffected()
s.NoError(err)
s.Equal(1, int(rowsAffected))
shard = s.newRandomShardRow(shardID, rangeID)
_, err = s.store.InsertIntoShards(newExecutionContext(), &shard)
s.Error(err) // TODO persistence layer should do proper error translation
}
func (s *historyShardSuite) TestInsertSelect() {
shardID := rand.Int31()
rangeID := int64(1)
shard := s.newRandomShardRow(shardID, rangeID)
result, err := s.store.InsertIntoShards(newExecutionContext(), &shard)
s.NoError(err)
rowsAffected, err := result.RowsAffected()
s.NoError(err)
s.Equal(1, int(rowsAffected))
filter := sqlplugin.ShardsFilter{
ShardID: shardID,
}
row, err := s.store.SelectFromShards(newExecutionContext(), filter)
s.NoError(err)
s.Equal(&shard, row)
}
func (s *historyShardSuite) TestInsertUpdate_Success() {
shardID := rand.Int31()
rangeID := int64(1)
shard := s.newRandomShardRow(shardID, rangeID)
rangeID += 100
result, err := s.store.InsertIntoShards(newExecutionContext(), &shard)
s.NoError(err)
rowsAffected, err := result.RowsAffected()
s.NoError(err)
s.Equal(1, int(rowsAffected))
shard = s.newRandomShardRow(shardID, rangeID)
result, err = s.store.UpdateShards(newExecutionContext(), &shard)
s.NoError(err)
rowsAffected, err = result.RowsAffected()
s.NoError(err)
s.Equal(1, int(rowsAffected))
}
func (s *historyShardSuite) TestUpdate_Fail() {
shardID := rand.Int31()
rangeID := int64(1)
shard := s.newRandomShardRow(shardID, rangeID)
result, err := s.store.UpdateShards(newExecutionContext(), &shard)
s.NoError(err)
rowsAffected, err := result.RowsAffected()
s.NoError(err)
s.Equal(0, int(rowsAffected))
}
func (s *historyShardSuite) TestInsertUpdateSelect() {
shardID := rand.Int31()
rangeID := int64(1)
shard := s.newRandomShardRow(shardID, rangeID)
rangeID += 100
result, err := s.store.InsertIntoShards(newExecutionContext(), &shard)
s.NoError(err)
rowsAffected, err := result.RowsAffected()
s.NoError(err)
s.Equal(1, int(rowsAffected))
shard = s.newRandomShardRow(shardID, rangeID)
result, err = s.store.UpdateShards(newExecutionContext(), &shard)
s.NoError(err)
rowsAffected, err = result.RowsAffected()
s.NoError(err)
s.Equal(1, int(rowsAffected))
filter := sqlplugin.ShardsFilter{
ShardID: shardID,
}
row, err := s.store.SelectFromShards(newExecutionContext(), filter)
s.NoError(err)
s.Equal(&shard, row)
}
func (s *historyShardSuite) TestInsertReadLock() {
shardID := rand.Int31()
rangeID := int64(rand.Int31())
shard := s.newRandomShardRow(shardID, rangeID)
result, err := s.store.InsertIntoShards(newExecutionContext(), &shard)
s.NoError(err)
rowsAffected, err := result.RowsAffected()
s.NoError(err)
s.Equal(1, int(rowsAffected))
tx, err := s.store.BeginTx(newExecutionContext())
s.NoError(err)
filter := sqlplugin.ShardsFilter{
ShardID: shardID,
}
shardRange, err := tx.ReadLockShards(newExecutionContext(), filter)
s.NoError(err)
s.Equal(rangeID, shardRange)
s.NoError(tx.Commit())
}
func (s *historyShardSuite) TestInsertWriteLock() {
shardID := rand.Int31()
rangeID := int64(rand.Int31())
shard := s.newRandomShardRow(shardID, rangeID)
result, err := s.store.InsertIntoShards(newExecutionContext(), &shard)
s.NoError(err)
rowsAffected, err := result.RowsAffected()
s.NoError(err)
s.Equal(1, int(rowsAffected))
tx, err := s.store.BeginTx(newExecutionContext())
s.NoError(err)
filter := sqlplugin.ShardsFilter{
ShardID: shardID,
}
shardRange, err := tx.WriteLockShards(newExecutionContext(), filter)
s.NoError(err)
s.Equal(rangeID, shardRange)
s.NoError(tx.Commit())
}
func (s *historyShardSuite) newRandomShardRow(
shardID int32,
rangeID int64,
) sqlplugin.ShardsRow {
return sqlplugin.ShardsRow{
ShardID: shardID,
RangeID: rangeID,
Data: shuffle.Bytes(testHistoryShardData),
DataEncoding: testHistoryShardEncoding,
}
}