*: make txnCommitBatchSize adjustable by SQL (#33507)

close #33508
pingcap · Mar 30, 2022 · d4ec947 · d4ec947
1 parent 191a2dc
commit d4ec947
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Showing 6 changed files with 28 additions and 3 deletions.
diff --git a/domain/sysvar_cache.go b/domain/sysvar_cache.go
@@ -243,6 +243,8 @@ func (do *Domain) checkEnableServerGlobalVar(name, sVal string) {
 		variable.StatsLoadSyncWait.Store(val)
 	case variable.TiDBStatsLoadPseudoTimeout:
 		variable.StatsLoadPseudoTimeout.Store(variable.TiDBOptOn(sVal))
+	case variable.TiDBTxnCommitBatchSize:
+		storekv.TxnCommitBatchSize.Store(uint64(variable.TidbOptInt64(sVal, int64(storekv.DefTxnCommitBatchSize))))
 	}
 	if err != nil {
 		logutil.BgLogger().Error(fmt.Sprintf("load global variable %s error", name), zap.Error(err))

diff --git a/executor/set_test.go b/executor/set_test.go
@@ -336,6 +336,14 @@ func TestSetVar(t *testing.T) {
 	tk.MustExec("set global tidb_store_limit = 100")
 	tk.MustQuery("select @@global.tidb_store_limit;").Check(testkit.Rows("100"))
 
+	tk.MustQuery("select @@global.tidb_txn_commit_batch_size;").Check(testkit.Rows("16384"))
+	tk.MustExec("set @@global.tidb_txn_commit_batch_size = 100")
+	tk.MustQuery("select @@global.tidb_txn_commit_batch_size;").Check(testkit.Rows("100"))
+	tk.MustExec("set @@global.tidb_txn_commit_batch_size = 0")
+	tk.MustQuery("select @@global.tidb_txn_commit_batch_size;").Check(testkit.Rows("1"))
+	tk.MustExec("set global tidb_txn_commit_batch_size = 100")
+	tk.MustQuery("select @@global.tidb_txn_commit_batch_size;").Check(testkit.Rows("100"))
+
 	tk.MustQuery("select @@session.tidb_metric_query_step;").Check(testkit.Rows("60"))
 	tk.MustExec("set @@session.tidb_metric_query_step = 120")
 	tk.MustExec("set @@session.tidb_metric_query_step = 9")

diff --git a/go.mod b/go.mod
@@ -63,7 +63,7 @@ require (
 	github.com/spf13/pflag v1.0.5
 	github.com/stretchr/testify v1.7.0
 	github.com/tiancaiamao/appdash v0.0.0-20181126055449-889f96f722a2
-	github.com/tikv/client-go/v2 v2.0.1-0.20220328083738-8489c3e8c3d9
+	github.com/tikv/client-go/v2 v2.0.1-0.20220329092050-6bf6951325ad
 	github.com/tikv/pd/client v0.0.0-20220307081149-841fa61e9710
 	github.com/twmb/murmur3 v1.1.3
 	github.com/uber/jaeger-client-go v2.22.1+incompatible

diff --git a/go.sum b/go.sum
@@ -749,8 +749,8 @@ github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/
 github.com/subosito/gotenv v1.2.0/go.mod h1:N0PQaV/YGNqwC0u51sEeR/aUtSLEXKX9iv69rRypqCw=
 github.com/tiancaiamao/appdash v0.0.0-20181126055449-889f96f722a2 h1:mbAskLJ0oJfDRtkanvQPiooDH8HvJ2FBh+iKT/OmiQQ=
 github.com/tiancaiamao/appdash v0.0.0-20181126055449-889f96f722a2/go.mod h1:2PfKggNGDuadAa0LElHrByyrz4JPZ9fFx6Gs7nx7ZZU=
-github.com/tikv/client-go/v2 v2.0.1-0.20220328083738-8489c3e8c3d9 h1:TgSywPECh84B5S6Z97jhMdQVrezPwUbOKbCZFie2kPI=
-github.com/tikv/client-go/v2 v2.0.1-0.20220328083738-8489c3e8c3d9/go.mod h1:0scaG+seu7L56apm+Gjz9vckyO7ABIzM6T7n00mrIXs=
+github.com/tikv/client-go/v2 v2.0.1-0.20220329092050-6bf6951325ad h1:Imm87gW7/Pra/NdUc7D3wkdtlZgo/iw0lSLIWZPiMS0=
+github.com/tikv/client-go/v2 v2.0.1-0.20220329092050-6bf6951325ad/go.mod h1:0scaG+seu7L56apm+Gjz9vckyO7ABIzM6T7n00mrIXs=
 github.com/tikv/pd/client v0.0.0-20220307081149-841fa61e9710 h1:jxgmKOscXSjaFEKQGRyY5qOpK8hLqxs2irb/uDJMtwk=
 github.com/tikv/pd/client v0.0.0-20220307081149-841fa61e9710/go.mod h1:AtvppPwkiyUgQlR1W9qSqfTB+OsOIu19jDCOxOsPkmU=
 github.com/tklauser/go-sysconf v0.3.9 h1:JeUVdAOWhhxVcU6Eqr/ATFHgXk/mmiItdKeJPev3vTo=

diff --git a/sessionctx/variable/sysvar.go b/sessionctx/variable/sysvar.go
@@ -529,6 +529,14 @@ var defaultSysVars = []*SysVar{
 		tikvstore.StoreLimit.Store(TidbOptInt64(val, DefTiDBStoreLimit))
 		return nil
 	}},
+	{Scope: ScopeGlobal, Name: TiDBTxnCommitBatchSize, Value: strconv.FormatUint(tikvstore.DefTxnCommitBatchSize, 10), Type: TypeUnsigned, MinValue: 1, MaxValue: 1 << 30,
+		GetGlobal: func(sv *SessionVars) (string, error) {
+			return strconv.FormatUint(tikvstore.TxnCommitBatchSize.Load(), 10), nil
+		},
+		SetGlobal: func(s *SessionVars, val string) error {
+			tikvstore.TxnCommitBatchSize.Store(uint64(TidbOptInt64(val, int64(tikvstore.DefTxnCommitBatchSize))))
+			return nil
+		}},
 	{Scope: ScopeGlobal, Name: TiDBRestrictedReadOnly, Value: BoolToOnOff(DefTiDBRestrictedReadOnly), Type: TypeBool, SetGlobal: func(s *SessionVars, val string) error {
 		on := TiDBOptOn(val)
 		if on {

diff --git a/sessionctx/variable/tidb_vars.go b/sessionctx/variable/tidb_vars.go
@@ -579,8 +579,15 @@ const (
 
 	// TiDBEnableLocalTxn indicates whether to enable Local Txn.
 	TiDBEnableLocalTxn = "tidb_enable_local_txn"
+
 	// TiDBTSOClientBatchMaxWaitTime indicates the max value of the TSO Batch Wait interval time of PD client.
 	TiDBTSOClientBatchMaxWaitTime = "tidb_tso_client_batch_max_wait_time"
+
+	// TiDBTxnCommitBatchSize is used to control the batch size of transaction commit related requests sent by TiDB to TiKV.
+	// If a single transaction has a large amount of writes, you can increase the batch size to improve the batch effect,
+	// setting too large will exceed TiKV's raft-entry-max-size limit and cause commit failure.
+	TiDBTxnCommitBatchSize = "tidb_txn_commit_batch_size"
+
 	// TiDBEnableTSOFollowerProxy indicates whether to enable the TSO Follower Proxy feature of PD client.
 	TiDBEnableTSOFollowerProxy = "tidb_enable_tso_follower_proxy"