Files
tasks/common/persistence/sql/sqlplugin/interfaces.go
T
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

162 lines
4.5 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 sqlplugin
import (
"context"
"database/sql"
"github.com/jmoiron/sqlx"
"go.temporal.io/server/common/config"
"go.temporal.io/server/common/log"
"go.temporal.io/server/common/metrics"
"go.temporal.io/server/common/resolver"
)
type (
DbKind int
)
const (
DbKindUnknown DbKind = iota
DbKindMain
DbKindVisibility
)
type VersionedBlob struct {
Version int64
Data []byte
DataEncoding string
}
type (
// Plugin defines the interface for any SQL database that needs to implement
Plugin interface {
CreateDB(dbKind DbKind, cfg *config.SQL, r resolver.ServiceResolver, l log.Logger, mh metrics.Handler) (DB, error)
CreateAdminDB(dbKind DbKind, cfg *config.SQL, r resolver.ServiceResolver, l log.Logger, mh metrics.Handler) (AdminDB, error)
}
// TableCRUD defines the API for interacting with the database tables
TableCRUD interface {
ClusterMetadata
Namespace
Visibility
QueueMessage
QueueMetadata
QueueV2Message
QueueV2Metadata
MatchingTask
MatchingTaskQueue
NexusEndpoints
HistoryNode
HistoryTree
HistoryShard
HistoryExecution
HistoryExecutionBuffer
HistoryExecutionActivity
HistoryExecutionChildWorkflow
HistoryExecutionTimer
HistoryExecutionRequestCancel
HistoryExecutionSignal
HistoryExecutionSignalRequest
HistoryImmediateTask
HistoryScheduledTask
HistoryTransferTask
HistoryTimerTask
HistoryReplicationTask
HistoryReplicationDLQTask
HistoryVisibilityTask
}
// AdminCRUD defines admin operations for CLI and test suites
AdminCRUD interface {
CreateSchemaVersionTables() error
ReadSchemaVersion(database string) (string, error)
UpdateSchemaVersion(database string, newVersion string, minCompatibleVersion string) error
WriteSchemaUpdateLog(oldVersion string, newVersion string, manifestMD5 string, desc string) error
ListTables(database string) ([]string, error)
DropTable(table string) error
DropAllTables(database string) error
CreateDatabase(database string) error
DropDatabase(database string) error
Exec(stmt string, args ...interface{}) error
}
// Tx defines the API for a SQL transaction
Tx interface {
TableCRUD
Commit() error
Rollback() error
}
// DB defines the API for regular SQL operations of a Temporal server
DB interface {
TableCRUD
BeginTx(ctx context.Context) (Tx, error)
PluginName() string
DbName() string
IsDupEntryError(err error) bool
Close() error
}
// AdminDB defines the API for admin SQL operations for CLI and testing suites
AdminDB interface {
AdminCRUD
PluginName() string
ExpectedVersion() string
VerifyVersion() error
Close() error
}
// Conn defines the API for a single database connection
Conn interface {
Rebind(query string) string
ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error)
NamedExecContext(ctx context.Context, query string, arg interface{}) (sql.Result, error)
GetContext(ctx context.Context, dest interface{}, query string, args ...interface{}) error
SelectContext(ctx context.Context, dest interface{}, query string, args ...interface{}) error
PrepareNamedContext(ctx context.Context, query string) (*sqlx.NamedStmt, error)
}
)
func (k DbKind) String() string {
switch k {
case DbKindMain:
return "main"
case DbKindVisibility:
return "visibility"
default:
return "unknown"
}
}