executor: reuse chunk row for insert on duplicate update (#12847) (#1…

…2999)

ddl/db_test.go

@@ -3030,16 +3030,17 @@ func (s *testDBSuite) TestAddNotNullColumnWhileInsertOnDupUpdate(c *C) {
 				return
 			default:
 			}
-			_, tk2Err = tk2.Exec("insert nn (a, b) values (1, 1) on duplicate key update a = 1, b = b + 1")
+			_, tk2Err = tk2.Exec("insert nn (a, b) values (1, 1) on duplicate key update a = 1, b = values(b) + 1")
 			if tk2Err != nil {
 				return
 			}
 		}
 	}()
-	tk1.MustExec("alter table nn add column c int not null default 0")
+	tk1.MustExec("alter table nn add column c int not null default 3 after a")
 	close(closeCh)
 	wg.Wait()
 	c.Assert(tk2Err, IsNil)
+	tk1.MustQuery("select * from nn").Check(testkit.Rows("1 3 2"))
 }
 
 type testMaxTableRowIDContext struct {

executor/insert.go

@@ -18,6 +18,7 @@ import (
 	"github.com/pingcap/parser/mysql"
 	"github.com/pingcap/tidb/expression"
 	"github.com/pingcap/tidb/kv"
+	"github.com/pingcap/tidb/table"
 	"github.com/pingcap/tidb/table/tables"
 	"github.com/pingcap/tidb/tablecodec"
 	"github.com/pingcap/tidb/types"
@@ -30,8 +31,12 @@ import (
 // InsertExec represents an insert executor.
 type InsertExec struct {
 	*InsertValues
-	OnDuplicate []*expression.Assignment
-	Priority    mysql.PriorityEnum
+	OnDuplicate    []*expression.Assignment
+	evalBuffer4Dup chunk.MutRow
+	curInsertVals  chunk.MutRow
+	row4Update     []types.Datum
+
+	Priority mysql.PriorityEnum
 }
 
 func (e *InsertExec) exec(rows [][]types.Datum) error {
@@ -151,6 +156,9 @@ func (e *InsertExec) Close() error {
 
 // Open implements the Executor Close interface.
 func (e *InsertExec) Open(ctx context.Context) error {
+	if e.OnDuplicate != nil {
+		e.initEvalBuffer4Dup()
+	}
 	if e.SelectExec != nil {
 		return e.SelectExec.Open(ctx)
 	}
@@ -177,32 +185,61 @@ func (e *InsertExec) updateDupRow(row toBeCheckedRow, handle int64, onDuplicate
 	return e.updateDupKeyValues(handle, newHandle, handleChanged, oldRow, updatedRow)
 }
 
+func (e *InsertExec) initEvalBuffer4Dup() {
+	// Use public columns for new row.
+	numCols := len(e.Table.Cols())
+	// Use writable columns for old row for update.
+	numWritableCols := len(e.Table.WritableCols())
+
+	evalBufferTypes := make([]*types.FieldType, 0, numCols+numWritableCols)
+
+	// Append the old row before the new row, to be consistent with "Schema4OnDuplicate" in the "Insert" PhysicalPlan.
+	for _, col := range e.Table.WritableCols() {
+		evalBufferTypes = append(evalBufferTypes, &col.FieldType)
+	}
+	for _, col := range e.Table.Cols() {
+		evalBufferTypes = append(evalBufferTypes, &col.FieldType)
+	}
+	if e.hasExtraHandle {
+		evalBufferTypes = append(evalBufferTypes, types.NewFieldType(mysql.TypeLonglong))
+	}
+	e.evalBuffer4Dup = chunk.MutRowFromTypes(evalBufferTypes)
+	e.curInsertVals = chunk.MutRowFromTypes(evalBufferTypes[numWritableCols:])
+	e.row4Update = make([]types.Datum, 0, len(evalBufferTypes))
+}
+
 // doDupRowUpdate updates the duplicate row.
 // TODO: Report rows affected.
 func (e *InsertExec) doDupRowUpdate(handle int64, oldRow []types.Datum, newRow []types.Datum,
 	cols []*expression.Assignment) ([]types.Datum, bool, int64, error) {
 	assignFlag := make([]bool, len(e.Table.WritableCols()))
 	// See http://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_values
-	e.ctx.GetSessionVars().CurrInsertValues = chunk.MutRowFromDatums(newRow).ToRow()
+	e.curInsertVals.SetDatums(newRow...)
+	e.ctx.GetSessionVars().CurrInsertValues = e.curInsertVals.ToRow()
 
 	// NOTE: In order to execute the expression inside the column assignment,
 	// we have to put the value of "oldRow" before "newRow" in "row4Update" to
 	// be consistent with "Schema4OnDuplicate" in the "Insert" PhysicalPlan.
-	row4Update := make([]types.Datum, 0, len(oldRow)+len(newRow))
-	row4Update = append(row4Update, oldRow...)
-	row4Update = append(row4Update, newRow...)
+	e.row4Update = e.row4Update[:0]
+	e.row4Update = append(e.row4Update, oldRow...)
+	e.row4Update = append(e.row4Update, newRow...)
 
 	// Update old row when the key is duplicated.
+	e.evalBuffer4Dup.SetDatums(e.row4Update...)
 	for _, col := range cols {
-		val, err1 := col.Expr.Eval(chunk.MutRowFromDatums(row4Update).ToRow())
+		val, err1 := col.Expr.Eval(e.evalBuffer4Dup.ToRow())
+		if err1 != nil {
+			return nil, false, 0, err1
+		}
+		e.row4Update[col.Col.Index], err1 = table.CastValue(e.ctx, val, col.Col.ToInfo())
 		if err1 != nil {
 			return nil, false, 0, errors.Trace(err1)
 		}
-		row4Update[col.Col.Index] = val
+		e.evalBuffer4Dup.SetDatum(col.Col.Index, e.row4Update[col.Col.Index])
 		assignFlag[col.Col.Index] = true
 	}
 
-	newData := row4Update[:len(oldRow)]
+	newData := e.row4Update[:len(oldRow)]
 	_, handleChanged, newHandle, err := updateRecord(e.ctx, handle, oldRow, newData, assignFlag, e.Table, true)
 	if err != nil {
 		return nil, false, 0, errors.Trace(err)

expression/column.go

@@ -336,6 +336,16 @@ func (col *Column) resolveIndices(schema *Schema) {
 	}
 }
 
+// ToInfo converts the expression.Column to model.ColumnInfo for casting values,
+// beware it doesn't fill all the fields of the model.ColumnInfo.
+func (col *Column) ToInfo() *model.ColumnInfo {
+	return &model.ColumnInfo{
+		ID:        col.ID,
+		Name:      col.ColName,
+		FieldType: *col.RetType,
+	}
+}
+
 // Column2Exprs will transfer column slice to expression slice.
 func Column2Exprs(cols []*Column) []Expression {
 	result := make([]Expression, 0, len(cols))

expression/explain.go

@@ -37,8 +37,8 @@ func (expr *ScalarFunction) ExplainInfo() string {
 }
 
 // ExplainInfo implements the Expression interface.
-func (expr *Column) ExplainInfo() string {
-	return expr.String()
+func (col *Column) ExplainInfo() string {
+	return col.String()
 }
 
 // ExplainInfo implements the Expression interface.