diff --git a/executor/builder.go b/executor/builder.go
index 3588a80bfd75f..1912f17eb5458 100644
--- a/executor/builder.go
+++ b/executor/builder.go
@@ -94,6 +94,7 @@ type executorBuilder struct {
 	readReplicaScope string
 	inUpdateStmt     bool
 	inDeleteStmt     bool
+	inInsertStmt     bool
 }
 
 // CTEStorages stores resTbl and iterInTbl for CTEExec.
@@ -795,6 +796,7 @@ func (b *executorBuilder) buildSetConfig(v *plannercore.SetConfig) Executor {
 }
 
 func (b *executorBuilder) buildInsert(v *plannercore.Insert) Executor {
+	b.inInsertStmt = true
 	if v.SelectPlan != nil {
 		// Try to update the forUpdateTS for insert/replace into select statements.
 		// Set the selectPlan parameter to nil to make it always update the forUpdateTS.
@@ -1420,6 +1422,12 @@ func (b *executorBuilder) buildProjection(v *plannercore.PhysicalProjection) Exe
 	if int64(v.StatsCount()) < int64(b.ctx.GetSessionVars().MaxChunkSize) {
 		e.numWorkers = 0
 	}
+
+	// Use un-parallel projection for query that write on memdb to avoid data race.
+	// See also https://github.com/pingcap/tidb/issues/26832
+	if b.inUpdateStmt || b.inDeleteStmt || b.inInsertStmt || b.hasLock {
+		e.numWorkers = 0
+	}
 	return e
 }
 
@@ -1936,6 +1944,7 @@ func (b *executorBuilder) buildSplitRegion(v *plannercore.SplitRegion) Executor
 }
 
 func (b *executorBuilder) buildUpdate(v *plannercore.Update) Executor {
+	b.inUpdateStmt = true
 	tblID2table := make(map[int64]table.Table, len(v.TblColPosInfos))
 	multiUpdateOnSameTable := make(map[int64]bool)
 	for _, info := range v.TblColPosInfos {
@@ -1976,7 +1985,6 @@ func (b *executorBuilder) buildUpdate(v *plannercore.Update) Executor {
 	if b.err != nil {
 		return nil
 	}
-	b.inUpdateStmt = true
 	updateExec := &UpdateExec{
 		baseExecutor:              base,
 		OrderedList:               v.OrderedList,
@@ -2009,6 +2017,7 @@ func getAssignFlag(ctx sessionctx.Context, v *plannercore.Update, schemaLen int)
 }
 
 func (b *executorBuilder) buildDelete(v *plannercore.Delete) Executor {
+	b.inDeleteStmt = true
 	tblID2table := make(map[int64]table.Table, len(v.TblColPosInfos))
 	for _, info := range v.TblColPosInfos {
 		tblID2table[info.TblID], _ = b.is.TableByID(info.TblID)
@@ -2021,7 +2030,6 @@ func (b *executorBuilder) buildDelete(v *plannercore.Delete) Executor {
 	if b.err != nil {
 		return nil
 	}
-	b.inDeleteStmt = true
 	base := newBaseExecutor(b.ctx, v.Schema(), v.ID(), selExec)
 	base.initCap = chunk.ZeroCapacity
 	deleteExec := &DeleteExec{