Skip FOR...UPDATE Clause in Warming Reads Queries

go/vt/vtgate/engine/route.go

@@ -60,6 +60,9 @@ type Route struct {
 	// Query specifies the query to be executed.
 	Query string
 
+	// QueryStatement is the parsed AST of Query
+	QueryStatement sqlparser.Statement
+
 	// FieldQuery specifies the query to be executed for a GetFieldInfo request.
 	FieldQuery string
 
@@ -512,6 +515,18 @@ func (route *Route) executeWarmingReplicaRead(ctx context.Context, vcursor VCurs
 		return
 	}
 
+	// Remove FOR UPDATE locks for warming reads if present
+	warmingQueries := queries
+	if modifiedQuery, ok := removeForUpdateLocks(route.QueryStatement); ok {
+		warmingQueries = make([]*querypb.BoundQuery, len(queries))
+		for i, query := range queries {
+			warmingQueries[i] = &querypb.BoundQuery{
+				Sql:           modifiedQuery,
+				BindVariables: query.BindVariables,
+			}
+		}
+	}
+
 	replicaVCursor := vcursor.CloneForReplicaWarming(ctx)
 	warmingReadsChannel := vcursor.GetWarmingReadsChannel()
 
@@ -527,7 +542,7 @@ func (route *Route) executeWarmingReplicaRead(ctx context.Context, vcursor VCurs
 				return
 			}
 
-			_, errs := replicaVCursor.ExecuteMultiShard(ctx, route, rss, queries, false /*rollbackOnError*/, false /*canAutocommit*/, route.FetchLastInsertID)
+			_, errs := replicaVCursor.ExecuteMultiShard(ctx, route, rss, warmingQueries, false /*rollbackOnError*/, false /*canAutocommit*/, route.FetchLastInsertID)
 			if len(errs) > 0 {
 				log.Warningf("Failed to execute warming replica read: %v", errs)
 			} else {
@@ -538,3 +553,23 @@ func (route *Route) executeWarmingReplicaRead(ctx context.Context, vcursor VCurs
 		log.Warning("Failed to execute warming replica read as pool is full")
 	}
 }
+
+func removeForUpdateLocks(stmt sqlparser.Statement) (string, bool) {
+	sel, ok := stmt.(*sqlparser.Select)
+	if !ok {
+		return "", false
+	}
+
+	// Check if this is a FOR UPDATE query
+	if sel.Lock != sqlparser.ForUpdateLock &&
+		sel.Lock != sqlparser.ForUpdateLockNoWait &&
+		sel.Lock != sqlparser.ForUpdateLockSkipLocked {
+		return "", false
+	}
+
+	// Remove the lock clause
+	sel.Lock = sqlparser.NoLock
+
+	// Convert back to SQL string
+	return sqlparser.String(sel), true
+}

go/vt/vtgate/engine/route_warming_reads_test.go

@@ -0,0 +1,142 @@
+/*
+Copyright 2024 The Vitess Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package engine
+
+import (
+	"context"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	"vitess.io/vitess/go/sqltypes"
+	"vitess.io/vitess/go/vt/sqlparser"
+	"vitess.io/vitess/go/vt/srvtopo"
+	"vitess.io/vitess/go/vt/vtgate/evalengine"
+	"vitess.io/vitess/go/vt/vtgate/vindexes"
+
+	querypb "vitess.io/vitess/go/vt/proto/query"
+)
+
+type warmingReadsVCursor struct {
+	*loggingVCursor
+	warmingReadsPercent     int
+	warmingReadsChannel     chan bool
+	warmingReadsExecuteFunc func(context.Context, Primitive, []*srvtopo.ResolvedShard, []*querypb.BoundQuery, bool, bool)
+}
+
+func (vc *warmingReadsVCursor) GetWarmingReadsPercent() int {
+	return vc.warmingReadsPercent
+}
+
+func (vc *warmingReadsVCursor) GetWarmingReadsChannel() chan bool {
+	return vc.warmingReadsChannel
+}
+
+func (vc *warmingReadsVCursor) CloneForReplicaWarming(ctx context.Context) VCursor {
+	clone := &warmingReadsVCursor{
+		loggingVCursor:          vc.loggingVCursor,
+		warmingReadsPercent:     vc.warmingReadsPercent,
+		warmingReadsChannel:     vc.warmingReadsChannel,
+		warmingReadsExecuteFunc: vc.warmingReadsExecuteFunc,
+	}
+	clone.onExecuteMultiShardFn = vc.warmingReadsExecuteFunc
+	return clone
+}
+
+func TestWarmingReadsSkipsForUpdate(t *testing.T) {
+	vindex, _ := vindexes.CreateVindex("hash", "", nil)
+	testCases := []struct {
+		name                 string
+		query                string
+		expectedWarmingQuery string
+	}{
+		{
+			name:                 "SELECT FOR UPDATE",
+			query:                "SELECT * FROM users WHERE id = 1 FOR UPDATE",
+			expectedWarmingQuery: "select * from users where id = 1",
+		},
+		{
+			name:                 "SELECT FOR UPDATE mixed case",
+			query:                "SELECT * FROM users WHERE id = 1 FoR UpDaTe",
+			expectedWarmingQuery: "select * from users where id = 1",
+		},
+		{
+			name:                 "SELECT FOR UPDATE with extra spaces",
+			query:                "SELECT * FROM users WHERE id = 1 FOR     UPDATE",
+			expectedWarmingQuery: "select * from users where id = 1",
+		},
+		{
+			name:                 "SELECT FOR UPDATE with comment",
+			query:                "SELECT * FROM users WHERE id = 1 FOR /* comment */ UPDATE",
+			expectedWarmingQuery: "select * from users where id = 1",
+		},
+		{
+			name:                 "Regular SELECT",
+			query:                "SELECT * FROM users WHERE id = 1",
+			expectedWarmingQuery: "SELECT * FROM users WHERE id = 1",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			route := NewRoute(
+				EqualUnique,
+				&vindexes.Keyspace{
+					Name:    "ks",
+					Sharded: true,
+				},
+				tc.query,
+				"dummy_select_field",
+			)
+			// Parse and set QueryStatement to match how Routes are created in production
+			parser, _ := sqlparser.NewTestParser().Parse(tc.query)
+			route.QueryStatement = parser
+			route.Vindex = vindex.(vindexes.SingleColumn)
+			route.Values = []evalengine.Expr{
+				evalengine.NewLiteralInt(1),
+			}
+
+			var warmingReadExecuted atomic.Bool
+			var capturedQuery string
+			vc := &warmingReadsVCursor{
+				loggingVCursor: &loggingVCursor{
+					shards:  []string{"-20", "20-"},
+					results: []*sqltypes.Result{defaultSelectResult},
+				},
+				warmingReadsPercent: 100,
+				warmingReadsChannel: make(chan bool, 1),
+			}
+			vc.warmingReadsExecuteFunc = func(ctx context.Context, primitive Primitive, rss []*srvtopo.ResolvedShard, queries []*querypb.BoundQuery, rollbackOnError, canAutocommit bool) {
+				if len(queries) > 0 {
+					capturedQuery = queries[0].Sql
+				}
+				warmingReadExecuted.Store(true)
+			}
+
+			_, err := route.TryExecute(context.Background(), vc, map[string]*querypb.BindVariable{}, false)
+			require.NoError(t, err)
+
+			require.Eventually(t, func() bool {
+				return warmingReadExecuted.Load()
+			}, time.Second, 10*time.Millisecond, "warming read should be executed")
+
+			require.Equal(t, tc.expectedWarmingQuery, capturedQuery, "warming read query should match expected")
+		})
+	}
+}

go/vt/vtgate/planbuilder/route.go

@@ -29,6 +29,7 @@ import (
 func WireupRoute(ctx *plancontext.PlanningContext, eroute *engine.Route, sel sqlparser.SelectStatement) (engine.Primitive, error) {
 	// prepare the queries we will pass down
 	eroute.Query = sqlparser.String(sel)
+	eroute.QueryStatement = sel
 	buffer := sqlparser.NewTrackedBuffer(sqlparser.FormatImpossibleQuery)
 	node := buffer.WriteNode(sel)
 	eroute.FieldQuery = node.ParsedQuery().Query