92 lines
2.9 KiB
Go
92 lines
2.9 KiB
Go
// Copyright 2021 PingCAP, Inc. Licensed under Apache-2.0.
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package utils
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import (
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"context"
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"database/sql"
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"strings"
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"github.com/pingcap/log"
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"github.com/pingcap/tidb/kv"
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"github.com/pingcap/tidb/sessionctx"
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"github.com/pingcap/tidb/util/sqlexec"
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"go.uber.org/zap"
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)
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var (
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// check sql.DB and sql.Conn implement QueryExecutor and DBExecutor
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_ DBExecutor = &sql.DB{}
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_ DBExecutor = &sql.Conn{}
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)
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// QueryExecutor is a interface for exec query
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type QueryExecutor interface {
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QueryContext(ctx context.Context, query string, args ...interface{}) (*sql.Rows, error)
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QueryRowContext(ctx context.Context, query string, args ...interface{}) *sql.Row
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}
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// StmtExecutor define both query and exec methods
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type StmtExecutor interface {
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QueryExecutor
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ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error)
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}
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// DBExecutor is a interface for statements and txn
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type DBExecutor interface {
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StmtExecutor
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BeginTx(ctx context.Context, opts *sql.TxOptions) (*sql.Tx, error)
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}
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// CheckLogBackupEnabled checks if LogBackup is enabled in cluster.
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// this mainly used in three places.
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// 1. GC worker resolve locks to scan more locks after safepoint. (every minute)
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// 2. Add index skipping use lightning.(every add index ddl)
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// 3. Telemetry of log backup feature usage (every 6 hours).
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// NOTE: this result shouldn't be cached by caller. because it may change every time in one cluster.
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func CheckLogBackupEnabled(ctx sessionctx.Context) bool {
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executor, ok := ctx.(sqlexec.RestrictedSQLExecutor)
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if !ok {
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// shouldn't happen
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log.Error("[backup] unable to translate executor from sessionctx")
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return false
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}
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enabled, err := IsLogBackupEnabled(executor)
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if err != nil {
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// if it failed by any reason. we can simply return true this time.
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// for GC worker it will scan more locks in one tick.
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// for Add index it will skip using lightning this time.
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// for Telemetry it will get a false positive usage count.
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log.Warn("[backup] check log backup config failed, ignore it", zap.Error(err))
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return true
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}
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return enabled
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}
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// IsLogBackupEnabled is used for br to check whether tikv has enabled log backup.
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// we use `sqlexec.RestrictedSQLExecutor` as parameter because it's easy to mock.
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// it should return error.
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func IsLogBackupEnabled(ctx sqlexec.RestrictedSQLExecutor) (bool, error) {
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valStr := "show config where name = 'log-backup.enable'"
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internalCtx := kv.WithInternalSourceType(context.Background(), kv.InternalTxnBR)
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rows, fields, errSQL := ctx.ExecRestrictedSQL(internalCtx, nil, valStr)
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if errSQL != nil {
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return false, errSQL
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}
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if len(rows) == 0 {
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// no rows mean not support log backup.
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return false, nil
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}
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for _, row := range rows {
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d := row.GetDatum(3, &fields[3].Column.FieldType)
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value, errField := d.ToString()
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if errField != nil {
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return false, errField
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}
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if strings.ToLower(value) == "false" {
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return false, nil
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}
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}
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return true, nil
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}
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