dml: support default expression cache when insert

ddl/sequence_test.go

@@ -34,6 +34,7 @@ type testSequenceSuite struct{ *testDBSuite }
 func (s *testSequenceSuite) TestCreateSequence(c *C) {
 	s.tk = testkit.NewTestKit(c, s.store)
 	s.tk.MustExec("use test")
+	s.tk.MustExec("drop sequence if exists seq")
 	s.tk.MustGetErrCode("create sequence `seq  `", mysql.ErrWrongTableName)
 
 	// increment should not be set as 0.
@@ -744,3 +745,29 @@ func (s *testSequenceSuite) TestUnflodSequence(c *C) {
 	// `select nextval(seq), a from t1 union select nextval(seq), a from t2`
 	// The executing order of nextval and lastval is implicit, don't make any assumptions on it.
 }
+
+// before this PR:
+// single insert consume: 50.498672ms
+// after this PR:
+// single insert consume: 33.213615ms
+// Notice: use go test -check.b Benchmarkxxx to test it.
+func (s *testSequenceSuite) BenchmarkInsertCacheDefaultExpr(c *C) {
+	s.tk = testkit.NewTestKit(c, s.store)
+	s.tk.MustExec("use test")
+	s.tk.MustExec("drop sequence if exists seq")
+	s.tk.MustExec("drop table if exists t")
+	s.tk.MustExec("create sequence seq")
+	s.tk.MustExec("create table t(a int default next value for seq)")
+	sql := "insert into t values "
+	for i := 0; i < 1000; i++ {
+		if i == 0 {
+			sql += "()"
+		} else {
+			sql += ",()"
+		}
+	}
+	c.ResetTimer()
+	for i := 0; i < c.N; i++ {
+		s.tk.MustExec(sql)
+	}
+}

executor/insert_common.go

@@ -497,7 +497,13 @@ func (e *InsertValues) getColDefaultValue(idx int, col *table.Column) (d types.D
 	if !col.DefaultIsExpr && e.colDefaultVals != nil && e.colDefaultVals[idx].valid {
 		return e.colDefaultVals[idx].val, nil
 	}
-	defaultVal, err := table.GetColDefaultValue(e.ctx, col.ToInfo())
+
+	var defaultVal types.Datum
+	if col.DefaultIsExpr && col.DefaultExpr != nil {
+		defaultVal, err = table.EvalColDefaultExpr(e.ctx, col.ToInfo(), col.DefaultExpr)
+	} else {
+		defaultVal, err = table.GetColDefaultValue(e.ctx, col.ToInfo())
+	}
 	if err != nil {
 		return types.Datum{}, err
 	}

go.sum

@@ -195,8 +195,6 @@ github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/pty v1.1.5/go.mod h1:9r2w37qlBe7rQ6e1fg1S/9xpWHSnaqNdHD3WcMdbPDA=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
-github.com/lawyerphx/parser v0.0.0-20200316023126-7af13c9e0b85 h1:my5oTuBLzT1knvQnwaF7RXxNuzvzqhioNM8OcHYF2/A=
-github.com/lawyerphx/parser v0.0.0-20200316023126-7af13c9e0b85/go.mod h1:9v0Edh8IbgjGYW2ArJr19E+bvL8zKahsFp+ixWeId+4=
 github.com/leodido/go-urn v1.1.0/go.mod h1:+cyI34gQWZcE1eQU7NVgKkkzdXDQHr1dBMtdAPozLkw=
 github.com/leodido/go-urn v1.2.0/go.mod h1:+8+nEpDfqqsY+g338gtMEUOtuK+4dEMhiQEgxpxOKII=
 github.com/lib/pq v1.1.1/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=

planner/core/planbuilder.go

@@ -1817,7 +1817,15 @@ func collectVisitInfoFromGrantStmt(sctx sessionctx.Context, vi []visitInfo, stmt
 }
 
 func (b *PlanBuilder) getDefaultValue(col *table.Column) (*expression.Constant, error) {
-	value, err := table.GetColDefaultValue(b.ctx, col.ToInfo())
+	var (
+		value types.Datum
+		err   error
+	)
+	if col.DefaultIsExpr && col.DefaultExpr != nil {
+		value, err = table.EvalColDefaultExpr(b.ctx, col.ToInfo(), col.DefaultExpr)
+	} else {
+		value, err = table.GetColDefaultValue(b.ctx, col.ToInfo())
+	}
 	if err != nil {
 		return nil, err
 	}

table/column.go

@@ -47,6 +47,8 @@ type Column struct {
 	*model.ColumnInfo
 	// If this column is a generated column, the expression will be stored here.
 	GeneratedExpr ast.ExprNode
+	// If this column has default expr value, this expression will be stored here.
+	DefaultExpr ast.ExprNode
 }
 
 // String implements fmt.Stringer interface.
@@ -82,6 +84,7 @@ func ToColumn(col *model.ColumnInfo) *Column {
 	return &Column{
 		col,
 		nil,
+		nil,
 	}
 }
 
@@ -379,6 +382,20 @@ func GetColDefaultValue(ctx sessionctx.Context, col *model.ColumnInfo) (types.Da
 	return getColDefaultExprValue(ctx, col, defaultValue.(string))
 }
 
+// EvalColDefaultExpr eval default expr node to explicit default value.
+func EvalColDefaultExpr(ctx sessionctx.Context, col *model.ColumnInfo, defaultExpr ast.ExprNode) (types.Datum, error) {
+	d, err := expression.EvalAstExpr(ctx, defaultExpr)
+	if err != nil {
+		return types.Datum{}, err
+	}
+	// Check the evaluated data type by cast.
+	value, err := CastValue(ctx, d, col)
+	if err != nil {
+		return types.Datum{}, err
+	}
+	return value, nil
+}
+
 func getColDefaultExprValue(ctx sessionctx.Context, col *model.ColumnInfo, defaultValue string) (types.Datum, error) {
 	var defaultExpr ast.ExprNode
 	expr := fmt.Sprintf("select %s", defaultValue)

table/tables/tables.go

@@ -122,6 +122,14 @@ func TableFromMeta(allocs autoid.Allocators, tblInfo *model.TableInfo) (table.Ta
 			}
 			col.GeneratedExpr = expr
 		}
+		// default value is expr.
+		if col.DefaultIsExpr {
+			expr, err := parseExpression(colInfo.DefaultValue.(string))
+			if err != nil {
+				return nil, err
+			}
+			col.DefaultExpr = expr
+		}
 		columns = append(columns, col)
 	}