topsql: distinguish the row and index operation type (#29044)

distsql/request_builder.go

@@ -235,7 +235,7 @@ func (builder *RequestBuilder) getKVPriority(sv *variable.SessionVars) int {
 }
 
 // SetFromSessionVars sets the following fields for "kv.Request" from session variables:
-// "Concurrency", "IsolationLevel", "NotFillCache", "ReplicaRead", "SchemaVar".
+// "Concurrency", "IsolationLevel", "NotFillCache", "TaskID", "Priority", "ReplicaRead", "ResourceGroupTagger".
 func (builder *RequestBuilder) SetFromSessionVars(sv *variable.SessionVars) *RequestBuilder {
 	if builder.Request.Concurrency == 0 {
 		// Concurrency may be set to 1 by SetDAGRequest
@@ -246,7 +246,7 @@ func (builder *RequestBuilder) SetFromSessionVars(sv *variable.SessionVars) *Req
 	builder.Request.TaskID = sv.StmtCtx.TaskID
 	builder.Request.Priority = builder.getKVPriority(sv)
 	builder.Request.ReplicaRead = sv.GetReplicaRead()
-	builder.SetResourceGroupTag(sv.StmtCtx)
+	builder.SetResourceGroupTagger(sv.StmtCtx)
 	return builder
 }
 
@@ -282,10 +282,10 @@ func (builder *RequestBuilder) SetFromInfoSchema(pis interface{}) *RequestBuilde
 	return builder
 }
 
-// SetResourceGroupTag sets the request resource group tag.
-func (builder *RequestBuilder) SetResourceGroupTag(sc *stmtctx.StatementContext) *RequestBuilder {
+// SetResourceGroupTagger sets the request resource group tagger.
+func (builder *RequestBuilder) SetResourceGroupTagger(sc *stmtctx.StatementContext) *RequestBuilder {
 	if variable.TopSQLEnabled() {
-		builder.Request.ResourceGroupTag = sc.GetResourceGroupTag()
+		builder.Request.ResourceGroupTagger = sc.GetResourceGroupTagger()
 	}
 	return builder
 }

executor/analyze.go

@@ -389,7 +389,7 @@ func (e *AnalyzeIndexExec) fetchAnalyzeResult(ranges []*ranger.Range, isNullRang
 	} else {
 		kvReqBuilder = builder.SetIndexRangesForTables(e.ctx.GetSessionVars().StmtCtx, []int64{e.tableID.GetStatisticsID()}, e.idxInfo.ID, ranges)
 	}
-	kvReqBuilder.SetResourceGroupTag(e.ctx.GetSessionVars().StmtCtx)
+	kvReqBuilder.SetResourceGroupTagger(e.ctx.GetSessionVars().StmtCtx)
 	kvReq, err := kvReqBuilder.
 		SetAnalyzeRequest(e.analyzePB).
 		SetStartTS(e.snapshot).
@@ -750,7 +750,7 @@ func (e *AnalyzeColumnsExec) open(ranges []*ranger.Range) error {
 func (e *AnalyzeColumnsExec) buildResp(ranges []*ranger.Range) (distsql.SelectResult, error) {
 	var builder distsql.RequestBuilder
 	reqBuilder := builder.SetHandleRangesForTables(e.ctx.GetSessionVars().StmtCtx, []int64{e.TableID.GetStatisticsID()}, e.handleCols != nil && !e.handleCols.IsInt(), ranges, nil)
-	builder.SetResourceGroupTag(e.ctx.GetSessionVars().StmtCtx)
+	builder.SetResourceGroupTagger(e.ctx.GetSessionVars().StmtCtx)
 	// Always set KeepOrder of the request to be true, in order to compute
 	// correct `correlation` of columns.
 	kvReq, err := reqBuilder.
@@ -1853,7 +1853,7 @@ func (e *AnalyzeFastExec) handleScanTasks(bo *tikv.Backoffer) (keysSize int, err
 	if e.ctx.GetSessionVars().GetReplicaRead().IsFollowerRead() {
 		snapshot.SetOption(kv.ReplicaRead, kv.ReplicaReadFollower)
 	}
-	setResourceGroupTagForTxn(e.ctx.GetSessionVars().StmtCtx, snapshot)
+	setResourceGroupTaggerForTxn(e.ctx.GetSessionVars().StmtCtx, snapshot)
 	for _, t := range e.scanTasks {
 		iter, err := snapshot.Iter(kv.Key(t.StartKey), kv.Key(t.EndKey))
 		if err != nil {
@@ -1874,7 +1874,7 @@ func (e *AnalyzeFastExec) handleSampTasks(workID int, step uint32, err *error) {
 	snapshot.SetOption(kv.NotFillCache, true)
 	snapshot.SetOption(kv.IsolationLevel, kv.SI)
 	snapshot.SetOption(kv.Priority, kv.PriorityLow)
-	setResourceGroupTagForTxn(e.ctx.GetSessionVars().StmtCtx, snapshot)
+	setResourceGroupTaggerForTxn(e.ctx.GetSessionVars().StmtCtx, snapshot)
 	readReplicaType := e.ctx.GetSessionVars().GetReplicaRead()
 	if readReplicaType.IsFollowerRead() {
 		snapshot.SetOption(kv.ReplicaRead, readReplicaType)

executor/batch_point_get.go

@@ -149,7 +149,7 @@ func (e *BatchPointGetExec) Open(context.Context) error {
 			},
 		})
 	}
-	setResourceGroupTagForTxn(stmtCtx, snapshot)
+	setResourceGroupTaggerForTxn(stmtCtx, snapshot)
 	var batchGetter kv.BatchGetter = snapshot
 	if txn.Valid() {
 		lock := e.tblInfo.Lock

executor/checksum.go

@@ -241,7 +241,7 @@ func (c *checksumContext) buildTableRequest(ctx sessionctx.Context, tableID int6
 	}
 
 	var builder distsql.RequestBuilder
-	builder.SetResourceGroupTag(ctx.GetSessionVars().StmtCtx)
+	builder.SetResourceGroupTagger(ctx.GetSessionVars().StmtCtx)
 	return builder.SetHandleRanges(ctx.GetSessionVars().StmtCtx, tableID, c.TableInfo.IsCommonHandle, ranges, nil).
 		SetChecksumRequest(checksum).
 		SetStartTS(c.StartTs).
@@ -258,7 +258,7 @@ func (c *checksumContext) buildIndexRequest(ctx sessionctx.Context, tableID int6
 	ranges := ranger.FullRange()
 
 	var builder distsql.RequestBuilder
-	builder.SetResourceGroupTag(ctx.GetSessionVars().StmtCtx)
+	builder.SetResourceGroupTagger(ctx.GetSessionVars().StmtCtx)
 	return builder.SetIndexRanges(ctx.GetSessionVars().StmtCtx, tableID, indexInfo.ID, ranges).
 		SetChecksumRequest(checksum).
 		SetStartTS(c.StartTs).

executor/executor.go

@@ -31,6 +31,7 @@ import (
 	"github.com/opentracing/opentracing-go"
 	"github.com/pingcap/errors"
 	"github.com/pingcap/failpoint"
+	"github.com/pingcap/kvproto/pkg/kvrpcpb"
 	"github.com/pingcap/tidb/config"
 	"github.com/pingcap/tidb/domain"
 	"github.com/pingcap/tidb/domain/infosync"
@@ -39,7 +40,6 @@ import (
 	"github.com/pingcap/tidb/kv"
 	"github.com/pingcap/tidb/meta"
 	"github.com/pingcap/tidb/meta/autoid"
-	"github.com/pingcap/tidb/parser"
 	"github.com/pingcap/tidb/parser/ast"
 	"github.com/pingcap/tidb/parser/auth"
 	"github.com/pingcap/tidb/parser/model"
@@ -968,18 +968,25 @@ func (e *SelectLockExec) Next(ctx context.Context, req *chunk.Chunk) error {
 }
 
 func newLockCtx(seVars *variable.SessionVars, lockWaitTime int64) *tikvstore.LockCtx {
-	var planDigest *parser.Digest
-	_, sqlDigest := seVars.StmtCtx.SQLDigest()
-	if variable.TopSQLEnabled() {
-		_, planDigest = seVars.StmtCtx.GetPlanDigest()
-	}
 	lockCtx := tikvstore.NewLockCtx(seVars.TxnCtx.GetForUpdateTS(), lockWaitTime, seVars.StmtCtx.GetLockWaitStartTime())
 	lockCtx.Killed = &seVars.Killed
 	lockCtx.PessimisticLockWaited = &seVars.StmtCtx.PessimisticLockWaited
 	lockCtx.LockKeysDuration = &seVars.StmtCtx.LockKeysDuration
 	lockCtx.LockKeysCount = &seVars.StmtCtx.LockKeysCount
 	lockCtx.LockExpired = &seVars.TxnCtx.LockExpire
-	lockCtx.ResourceGroupTag = resourcegrouptag.EncodeResourceGroupTag(sqlDigest, planDigest)
+	lockCtx.ResourceGroupTagger = func(req *kvrpcpb.PessimisticLockRequest) []byte {
+		if req == nil {
+			return nil
+		}
+		if len(req.Mutations) == 0 {
+			return nil
+		}
+		if mutation := req.Mutations[0]; mutation != nil {
+			label := resourcegrouptag.GetResourceGroupLabelByKey(mutation.Key)
+			return seVars.StmtCtx.GetResourceGroupTagByLabel(label)
+		}
+		return nil
+	}
 	lockCtx.OnDeadlock = func(deadlock *tikverr.ErrDeadlock) {
 		cfg := config.GetGlobalConfig()
 		if deadlock.IsRetryable && !cfg.PessimisticTxn.DeadlockHistoryCollectRetryable {
@@ -1896,8 +1903,8 @@ func FillVirtualColumnValue(virtualRetTypes []*types.FieldType, virtualColumnInd
 	return nil
 }
 
-func setResourceGroupTagForTxn(sc *stmtctx.StatementContext, snapshot kv.Snapshot) {
+func setResourceGroupTaggerForTxn(sc *stmtctx.StatementContext, snapshot kv.Snapshot) {
 	if snapshot != nil && variable.TopSQLEnabled() {
-		snapshot.SetOption(kv.ResourceGroupTag, sc.GetResourceGroupTag())
+		snapshot.SetOption(kv.ResourceGroupTagger, sc.GetResourceGroupTagger())
 	}
 }

executor/executor_test.go

@@ -8692,6 +8692,7 @@ func (s *testResourceTagSuite) TestResourceGroupTag(c *C) {
 	defer failpoint.Disable("github.com/pingcap/tidb/store/mockstore/unistore/unistoreRPCClientSendHook")
 
 	var sqlDigest, planDigest *parser.Digest
+	var tagLabel tipb.ResourceGroupTagLabel
 	checkFn := func() {}
 	unistore.UnistoreRPCClientSendHook = func(req *tikvrpc.Request) {
 		var startKey []byte
@@ -8734,6 +8735,7 @@ func (s *testResourceTagSuite) TestResourceGroupTag(c *C) {
 		c.Assert(err, IsNil)
 		sqlDigest = parser.NewDigest(tag.SqlDigest)
 		planDigest = parser.NewDigest(tag.PlanDigest)
+		tagLabel = *tag.Label
 		checkFn()
 	}
 
@@ -8743,19 +8745,78 @@ func (s *testResourceTagSuite) TestResourceGroupTag(c *C) {
 	}
 
 	cases := []struct {
-		sql    string
-		ignore bool
+		sql       string
+		tagLabels []tipb.ResourceGroupTagLabel
+		ignore    bool
 	}{
-		{sql: "insert into t values(1,1),(2,2),(3,3)"},
-		{sql: "select * from t use index (idx) where a=1"},
-		{sql: "select * from t use index (idx) where a in (1,2,3)"},
-		{sql: "select * from t use index (idx) where a>1"},
-		{sql: "select * from t where b>1"},
-		{sql: "begin pessimistic", ignore: true},
-		{sql: "insert into t values(4,4)"},
-		{sql: "commit", ignore: true},
-		{sql: "update t set a=5,b=5 where a=5"},
-		{sql: "replace into t values(6,6)"},
+		{
+			sql: "insert into t values(1,1),(2,2),(3,3)",
+			tagLabels: []tipb.ResourceGroupTagLabel{
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelIndex,
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelIndex,
+			},
+		},
+		{
+			sql: "select * from t use index (idx) where a=1",
+			tagLabels: []tipb.ResourceGroupTagLabel{
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelIndex,
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelRow,
+			},
+		},
+		{
+			sql: "select * from t use index (idx) where a in (1,2,3)",
+			tagLabels: []tipb.ResourceGroupTagLabel{
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelIndex,
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelRow,
+			},
+		},
+		{
+			sql: "select * from t use index (idx) where a>1",
+			tagLabels: []tipb.ResourceGroupTagLabel{
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelIndex,
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelRow,
+			},
+		},
+		{
+			sql: "select * from t where b>1",
+			tagLabels: []tipb.ResourceGroupTagLabel{
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelRow,
+			},
+		},
+		{
+			sql: "select a from t use index (idx) where a>1",
+			tagLabels: []tipb.ResourceGroupTagLabel{
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelIndex,
+			},
+		},
+		{
+			sql:    "begin pessimistic",
+			ignore: true,
+		},
+		{
+			sql: "insert into t values(4,4)",
+			tagLabels: []tipb.ResourceGroupTagLabel{
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelIndex,
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelRow,
+			},
+		},
+		{
+			sql:    "commit",
+			ignore: true,
+		},
+		{
+			sql: "update t set a=5,b=5 where a=5",
+			tagLabels: []tipb.ResourceGroupTagLabel{
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelIndex,
+			},
+		},
+		{
+			sql: "replace into t values(6,6)",
+			tagLabels: []tipb.ResourceGroupTagLabel{
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelIndex,
+				tipb.ResourceGroupTagLabel_ResourceGroupTagLabelIndex,
+			},
+		},
 	}
 	for _, ca := range cases {
 		resetVars()
@@ -8777,6 +8838,10 @@ func (s *testResourceTagSuite) TestResourceGroupTag(c *C) {
 			}
 			c.Assert(sqlDigest.String(), Equals, expectSQLDigest.String(), commentf)
 			c.Assert(planDigest.String(), Equals, expectPlanDigest.String())
+			if len(ca.tagLabels) > 0 {
+				c.Assert(tagLabel, Equals, ca.tagLabels[0])
+				ca.tagLabels = ca.tagLabels[1:] // next label
+			}
 			checkCnt++
 		}
 

executor/insert.go

@@ -66,7 +66,7 @@ func (e *InsertExec) exec(ctx context.Context, rows [][]types.Datum) error {
 	if err != nil {
 		return err
 	}
-	setResourceGroupTagForTxn(sessVars.StmtCtx, txn)
+	setResourceGroupTaggerForTxn(sessVars.StmtCtx, txn)
 	txnSize := txn.Size()
 	sessVars.StmtCtx.AddRecordRows(uint64(len(rows)))
 	// If you use the IGNORE keyword, duplicate-key error that occurs while executing the INSERT statement are ignored.

executor/point_get.go

@@ -190,7 +190,7 @@ func (e *PointGetExecutor) Open(context.Context) error {
 			panic("point get replica option fail")
 		}
 	})
-	setResourceGroupTagForTxn(e.ctx.GetSessionVars().StmtCtx, e.snapshot)
+	setResourceGroupTaggerForTxn(e.ctx.GetSessionVars().StmtCtx, e.snapshot)
 	return nil
 }
 

executor/replace.go

@@ -222,7 +222,7 @@ func (e *ReplaceExec) exec(ctx context.Context, newRows [][]types.Datum) error {
 			defer snapshot.SetOption(kv.CollectRuntimeStats, nil)
 		}
 	}
-	setResourceGroupTagForTxn(e.ctx.GetSessionVars().StmtCtx, txn)
+	setResourceGroupTaggerForTxn(e.ctx.GetSessionVars().StmtCtx, txn)
 	prefetchStart := time.Now()
 	// Use BatchGet to fill cache.
 	// It's an optimization and could be removed without affecting correctness.

executor/update.go

@@ -274,7 +274,7 @@ func (e *UpdateExec) updateRows(ctx context.Context) (int, error) {
 		if variable.TopSQLEnabled() {
 			txn, err := e.ctx.Txn(true)
 			if err == nil {
-				txn.SetOption(kv.ResourceGroupTag, e.ctx.GetSessionVars().StmtCtx.GetResourceGroupTag())
+				txn.SetOption(kv.ResourceGroupTagger, e.ctx.GetSessionVars().StmtCtx.GetResourceGroupTagger())
 			}
 		}
 		for rowIdx := 0; rowIdx < chk.NumRows(); rowIdx++ {

go.mod

@@ -65,7 +65,7 @@ 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 v2.0.0-alpha.0.20211115071040-a3f1c41ac1a0
+	github.com/tikv/client-go/v2 v2.0.0-alpha.0.20211118154139-b11da6307c6f
 	github.com/tikv/pd v1.1.0-beta.0.20211104095303-69c86d05d379
 	github.com/twmb/murmur3 v1.1.3
 	github.com/uber/jaeger-client-go v2.22.1+incompatible

go.sum

@@ -710,8 +710,8 @@ github.com/tiancaiamao/appdash v0.0.0-20181126055449-889f96f722a2/go.mod h1:2PfK
 github.com/tidwall/gjson v1.3.5/go.mod h1:P256ACg0Mn+j1RXIDXoss50DeIABTYK1PULOJHhxOls=
 github.com/tidwall/match v1.0.1/go.mod h1:LujAq0jyVjBy028G1WhWfIzbpQfMO8bBZ6Tyb0+pL9E=
 github.com/tidwall/pretty v1.0.0/go.mod h1:XNkn88O1ChpSDQmQeStsy+sBenx6DDtFZJxhVysOjyk=
-github.com/tikv/client-go/v2 v2.0.0-alpha.0.20211115071040-a3f1c41ac1a0 h1:c12Pv8Xks4oubDr/uHHxrlBkwGJFqKZUEIUemHV794g=
-github.com/tikv/client-go/v2 v2.0.0-alpha.0.20211115071040-a3f1c41ac1a0/go.mod h1:iiwtsCxcbNLK5i9VRYGvdcihgHXTKy2ukWjoaJsrphg=
+github.com/tikv/client-go/v2 v2.0.0-alpha.0.20211118154139-b11da6307c6f h1:UyJjp3wGIjf1edGiQiIdAtL5QFqaqR4+s3LDwUZU7NY=
+github.com/tikv/client-go/v2 v2.0.0-alpha.0.20211118154139-b11da6307c6f/go.mod h1:BEAS0vXm5BorlF/HTndqGwcGDvaiwe7B7BkfgwwZMJ4=
 github.com/tikv/pd v1.1.0-beta.0.20211029083450-e65f0c55b6ae/go.mod h1:varH0IE0jJ9E9WN2Ei/N6pajMlPkcXdDEf7f5mmsUVQ=
 github.com/tikv/pd v1.1.0-beta.0.20211104095303-69c86d05d379 h1:nFm1jQDz1iRktoyV2SyM5zVk6+PJHQNunJZ7ZJcqzAo=
 github.com/tikv/pd v1.1.0-beta.0.20211104095303-69c86d05d379/go.mod h1:y+09hAUXJbrd4c0nktL74zXDDuD7atGtfOKxL90PCOE=

infoschema/cluster_tables_serial_test.go

@@ -43,6 +43,7 @@ import (
 	"github.com/pingcap/tidb/util/resourcegrouptag"
 	"github.com/pingcap/tidb/util/set"
 	"github.com/pingcap/tidb/util/testutil"
+	"github.com/pingcap/tipb/go-tipb"
 	"github.com/stretchr/testify/require"
 	"google.golang.org/grpc"
 )
@@ -160,10 +161,10 @@ func SubTestTestDataLockWaits(s *clusterTablesSuite) func(*testing.T) {
 		_, digest1 := parser.NormalizeDigest("select * from test_data_lock_waits for update")
 		_, digest2 := parser.NormalizeDigest("update test_data_lock_waits set f1=1 where id=2")
 		s.store.(mockstorage.MockLockWaitSetter).SetMockLockWaits([]*deadlock.WaitForEntry{
-			{Txn: 1, WaitForTxn: 2, Key: []byte("key1"), ResourceGroupTag: resourcegrouptag.EncodeResourceGroupTag(digest1, nil)},
-			{Txn: 3, WaitForTxn: 4, Key: []byte("key2"), ResourceGroupTag: resourcegrouptag.EncodeResourceGroupTag(digest2, nil)},
+			{Txn: 1, WaitForTxn: 2, Key: []byte("key1"), ResourceGroupTag: resourcegrouptag.EncodeResourceGroupTag(digest1, nil, tipb.ResourceGroupTagLabel_ResourceGroupTagLabelUnknown)},
+			{Txn: 3, WaitForTxn: 4, Key: []byte("key2"), ResourceGroupTag: resourcegrouptag.EncodeResourceGroupTag(digest2, nil, tipb.ResourceGroupTagLabel_ResourceGroupTagLabelUnknown)},
 			// Invalid digests
-			{Txn: 5, WaitForTxn: 6, Key: []byte("key3"), ResourceGroupTag: resourcegrouptag.EncodeResourceGroupTag(nil, nil)},
+			{Txn: 5, WaitForTxn: 6, Key: []byte("key3"), ResourceGroupTag: resourcegrouptag.EncodeResourceGroupTag(nil, nil, tipb.ResourceGroupTagLabel_ResourceGroupTagLabelUnknown)},
 			{Txn: 7, WaitForTxn: 8, Key: []byte("key4"), ResourceGroupTag: []byte("asdfghjkl")},
 		})
 

kv/kv.go

@@ -30,6 +30,7 @@ import (
 	tikvstore "github.com/tikv/client-go/v2/kv"
 	"github.com/tikv/client-go/v2/oracle"
 	"github.com/tikv/client-go/v2/tikv"
+	"github.com/tikv/client-go/v2/tikvrpc"
 )
 
 // UnCommitIndexKVFlag uses to indicate the index key/value is no need to commit.
@@ -335,8 +336,8 @@ type Request struct {
 	IsStaleness bool
 	// MatchStoreLabels indicates the labels the store should be matched
 	MatchStoreLabels []*metapb.StoreLabel
-	// ResourceGroupTag indicates the kv request task group.
-	ResourceGroupTag []byte
+	// ResourceGroupTagger indicates the kv request task group tagger.
+	ResourceGroupTagger tikvrpc.ResourceGroupTagger
 }
 
 const (

kv/option.go

@@ -62,10 +62,13 @@ const (
 	IsStalenessReadOnly
 	// MatchStoreLabels indicates the labels the store should be matched
 	MatchStoreLabels
-	// ResourceGroupTag indicates the resource group of the kv request.
+	// ResourceGroupTag indicates the resource group tag of the kv request.
 	ResourceGroupTag
+	// ResourceGroupTagger can be used to set the ResourceGroupTag dynamically according to the request content. It will be used only when ResourceGroupTag is nil.
+	ResourceGroupTagger
 	// KVFilter indicates the filter to ignore key-values in the transaction's memory buffer.
 	KVFilter
+
 	// SnapInterceptor is used for setting the interceptor for snapshot
 	SnapInterceptor
 )

session/session.go

@@ -544,7 +544,7 @@ func (s *session) doCommit(ctx context.Context) error {
 	}
 	s.txn.SetOption(kv.EnableAsyncCommit, sessVars.EnableAsyncCommit)
 	s.txn.SetOption(kv.Enable1PC, sessVars.Enable1PC)
-	s.txn.SetOption(kv.ResourceGroupTag, sessVars.StmtCtx.GetResourceGroupTag())
+	s.txn.SetOption(kv.ResourceGroupTagger, sessVars.StmtCtx.GetResourceGroupTagger())
 	// priority of the sysvar is lower than `start transaction with causal consistency only`
 	if val := s.txn.GetOption(kv.GuaranteeLinearizability); val == nil || val.(bool) {
 		// We needn't ask the TiKV client to guarantee linearizability for auto-commit transactions