ddl: improve priority of suppressErrorTooLongKeyKey for DM (#55164)

ddl/index.go

@@ -51,6 +51,7 @@ import (
 	"github.com/pingcap/tidb/util/dbterror"
 	"github.com/pingcap/tidb/util/logutil"
 	decoder "github.com/pingcap/tidb/util/rowDecoder"
+	"github.com/pingcap/tidb/util/stringutil"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/tikv/client-go/v2/oracle"
 	"github.com/tikv/client-go/v2/tikv"
@@ -65,8 +66,20 @@ const (
 
 var (
 	telemetryAddIndexIngestUsage = metrics.TelemetryAddIndexIngestCnt
+	// SuppressErrorTooLongKeyKey is used by SchemaTracker to suppress err too long key error
+	SuppressErrorTooLongKeyKey stringutil.StringerStr = "suppressErrorTooLongKeyKey"
 )
 
+func suppressErrorTooLongKeyForSchemaTracker(sctx sessionctx.Context) bool {
+	if sctx == nil {
+		return false
+	}
+	if suppress, ok := sctx.Value(SuppressErrorTooLongKeyKey).(bool); ok && suppress {
+		return true
+	}
+	return false
+}
+
 func buildIndexColumns(ctx sessionctx.Context, columns []*model.ColumnInfo, indexPartSpecifications []*ast.IndexPartSpecification) ([]*model.IndexColumn, error) {
 	// Build offsets.
 	idxParts := make([]*model.IndexColumn, 0, len(indexPartSpecifications))
@@ -91,7 +104,7 @@ func buildIndexColumns(ctx sessionctx.Context, columns []*model.ColumnInfo, inde
 		sumLength += indexColumnLength
 
 		// The sum of all lengths must be shorter than the max length for prefix.
-		if sumLength > maxIndexLength {
+		if !suppressErrorTooLongKeyForSchemaTracker(ctx) && sumLength > maxIndexLength {
 			// The multiple column index and the unique index in which the length sum exceeds the maximum size
 			// will return an error instead produce a warning.
 			if ctx == nil || ctx.GetSessionVars().StrictSQLMode || mysql.HasUniKeyFlag(col.GetFlag()) || len(indexPartSpecifications) > 1 {
@@ -203,9 +216,11 @@ func checkIndexColumn(ctx sessionctx.Context, col *model.ColumnInfo, indexColumn
 	}
 	// Specified length must be shorter than the max length for prefix.
 	maxIndexLength := config.GetGlobalConfig().MaxIndexLength
-	if indexColumnLen > maxIndexLength && (ctx == nil || ctx.GetSessionVars().StrictSQLMode) {
-		// return error in strict sql mode
-		return dbterror.ErrTooLongKey.GenWithStackByArgs(maxIndexLength)
+	if indexColumnLen > maxIndexLength {
+		if ctx == nil || (ctx.GetSessionVars().StrictSQLMode && !suppressErrorTooLongKeyForSchemaTracker(ctx)) {
+			// return error in strict sql mode
+			return dbterror.ErrTooLongKey.GenWithStackByArgs(maxIndexLength)
+		}
 	}
 	return nil
 }

ddl/schematracker/dm_tracker.go

@@ -45,13 +45,14 @@ import (
 	"github.com/pingcap/tidb/util/dbterror"
 )
 
-var _ ddl.DDL = SchemaTracker{}
-
-// SchemaTracker is used to track schema changes by DM. It implements DDL interface and by applying DDL, it updates the
-// table structure to keep tracked with upstream changes.
-// It embeds an InfoStore which stores DBInfo and TableInfo. The DBInfo and TableInfo can be treated as immutable, so
-// after reading them by SchemaByName or TableByName, later modifications made by SchemaTracker will not change them.
-// SchemaTracker is not thread-safe.
+// SchemaTracker is used to track schema changes by DM. It implements DDL
+// interface and by applying DDL, it updates the table structure to keep tracked
+// with upstream changes.
+//
+// It embeds an InfoStore which stores DBInfo and TableInfo. The DBInfo and
+// TableInfo can be treated as immutable, so after reading them by SchemaByName
+// or TableByName, later modifications made by SchemaTracker will not change
+// them. SchemaTracker is not thread-safe.
 type SchemaTracker struct {
 	*InfoStore
 }
@@ -182,13 +183,12 @@ func (d SchemaTracker) CreateTable(ctx sessionctx.Context, s *ast.CreateTableStm
 		return infoschema.ErrDatabaseNotExists.GenWithStackByArgs(ident.Schema)
 	}
 	// suppress ErrTooLongKey
-	strictSQLModeBackup := ctx.GetSessionVars().StrictSQLMode
-	ctx.GetSessionVars().StrictSQLMode = false
+	ctx.SetValue(ddl.SuppressErrorTooLongKeyKey, true)
 	// support drop PK
 	enableClusteredIndexBackup := ctx.GetSessionVars().EnableClusteredIndex
 	ctx.GetSessionVars().EnableClusteredIndex = variable.ClusteredIndexDefModeOff
 	defer func() {
-		ctx.GetSessionVars().StrictSQLMode = strictSQLModeBackup
+		ctx.ClearValue(ddl.SuppressErrorTooLongKeyKey)
 		ctx.GetSessionVars().EnableClusteredIndex = enableClusteredIndexBackup
 	}()
 

ddl/schematracker/dm_tracker_test.go

@@ -86,6 +86,10 @@ func TestCreateTableLongIndex(t *testing.T) {
 	tracker := schematracker.NewSchemaTracker(2)
 	tracker.CreateTestDB()
 	execCreate(t, tracker, sql)
+	sql2 := "create table test.t2 (c1 int, c2 blob, c3 varchar(64), unique index idx_c2(c2(555555)));"
+	execCreate(t, tracker, sql2)
+	sql3 := "create table test.t3 (c1 int, c2 blob, c3 varchar(64), index idx_c2_c3(c3, c2(555555)));"
+	execCreate(t, tracker, sql3)
 }
 
 func execAlter(t *testing.T, tracker schematracker.SchemaTracker, sql string) {