expression: use a bool arg for Expression.ConstItem (pingcap#49495)

close pingcap#49492

pkg/expression/aggregation/base_func.go

@@ -145,7 +145,7 @@ func (a *baseFuncDesc) typeInfer4ApproxPercentile(ctx sessionctx.Context) error
 		return errors.New("APPROX_PERCENTILE should take 2 arguments")
 	}
 
-	if !a.Args[1].ConstItem(ctx.GetSessionVars().StmtCtx) {
+	if !a.Args[1].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) {
 		return errors.New("APPROX_PERCENTILE should take a constant expression as percentage argument")
 	}
 	percent, isNull, err := a.Args[1].EvalInt(ctx, chunk.Row{})

pkg/expression/builtin.go

@@ -52,11 +52,8 @@ type baseBuiltinFunc struct {
 	pbCode       tipb.ScalarFuncSig
 	ctor         collate.Collator
 
-	childrenVectorized bool
-	childrenReversed   bool
-
+	childrenVectorized     bool
 	childrenVectorizedOnce *sync.Once
-	childrenReversedOnce   *sync.Once
 
 	collationInfo
 }
@@ -120,7 +117,6 @@ func newBaseBuiltinFunc(ctx sessionctx.Context, funcName string, args []Expressi
 	bf := baseBuiltinFunc{
 		bufAllocator:           newLocalColumnPool(),
 		childrenVectorizedOnce: new(sync.Once),
-		childrenReversedOnce:   new(sync.Once),
 
 		args: args,
 		tp:   tp,
@@ -207,7 +203,6 @@ func newBaseBuiltinFuncWithTp(ctx sessionctx.Context, funcName string, args []Ex
 	bf = baseBuiltinFunc{
 		bufAllocator:           newLocalColumnPool(),
 		childrenVectorizedOnce: new(sync.Once),
-		childrenReversedOnce:   new(sync.Once),
 
 		args: args,
 		tp:   fieldType,
@@ -269,7 +264,6 @@ func newBaseBuiltinFuncWithFieldTypes(ctx sessionctx.Context, funcName string, a
 	bf = baseBuiltinFunc{
 		bufAllocator:           newLocalColumnPool(),
 		childrenVectorizedOnce: new(sync.Once),
-		childrenReversedOnce:   new(sync.Once),
 
 		args: args,
 		tp:   fieldType,
@@ -289,7 +283,6 @@ func newBaseBuiltinFuncWithFieldType(tp *types.FieldType, args []Expression) (ba
 	bf := baseBuiltinFunc{
 		bufAllocator:           newLocalColumnPool(),
 		childrenVectorizedOnce: new(sync.Once),
-		childrenReversedOnce:   new(sync.Once),
 
 		args: args,
 		tp:   tp,
@@ -414,7 +407,6 @@ func (b *baseBuiltinFunc) cloneFrom(from *baseBuiltinFunc) {
 	b.pbCode = from.pbCode
 	b.bufAllocator = newLocalColumnPool()
 	b.childrenVectorizedOnce = new(sync.Once)
-	b.childrenReversedOnce = new(sync.Once)
 	b.ctor = from.ctor
 }
 
@@ -1020,9 +1012,6 @@ func (b *baseBuiltinFunc) MemoryUsage() (sum int64) {
 	if b.childrenVectorizedOnce != nil {
 		sum += onceSize
 	}
-	if b.childrenReversedOnce != nil {
-		sum += onceSize
-	}
 	for _, e := range b.args {
 		sum += e.MemoryUsage()
 	}

pkg/expression/builtin_cast.go

@@ -2233,7 +2233,7 @@ func WrapWithCastAsDecimal(ctx sessionctx.Context, expr Expression) Expression {
 	tp.AddFlag(expr.GetType().GetFlag() & (mysql.UnsignedFlag | mysql.NotNullFlag))
 	castExpr := BuildCastFunction(ctx, expr, tp)
 	// For const item, we can use find-grained precision and scale by the result.
-	if castExpr.ConstItem(ctx.GetSessionVars().StmtCtx) {
+	if castExpr.ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) {
 		val, isnull, err := castExpr.EvalDecimal(ctx, chunk.Row{})
 		if !isnull && err == nil {
 			precision, frac := val.PrecisionAndFrac()

pkg/expression/builtin_encryption_vec.go

@@ -72,7 +72,7 @@ func (b *builtinAesDecryptSig) vecEvalString(ctx EvalContext, input *chunk.Chunk
 	}
 
 	isWarning := !b.ivRequired && len(b.args) == 3
-	isConstKey := b.args[1].ConstItem(ctx.GetSessionVars().StmtCtx)
+	isConstKey := b.args[1].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache)
 
 	var key []byte
 	if isConstKey {
@@ -158,7 +158,7 @@ func (b *builtinAesEncryptIVSig) vecEvalString(ctx EvalContext, input *chunk.Chu
 		return errors.Errorf("unsupported block encryption mode - %v", b.modeName)
 	}
 
-	isConst := b.args[1].ConstItem(ctx.GetSessionVars().StmtCtx)
+	isConst := b.args[1].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache)
 	var key []byte
 	if isConst {
 		key = encrypt.DeriveKeyMySQL(keyBuf.GetBytes(0), b.keySize)
@@ -331,7 +331,7 @@ func (b *builtinAesDecryptIVSig) vecEvalString(ctx EvalContext, input *chunk.Chu
 		return errors.Errorf("unsupported block encryption mode - %v", b.modeName)
 	}
 
-	isConst := b.args[1].ConstItem(ctx.GetSessionVars().StmtCtx)
+	isConst := b.args[1].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache)
 	var key []byte
 	if isConst {
 		key = encrypt.DeriveKeyMySQL(keyBuf.GetBytes(0), b.keySize)
@@ -672,7 +672,7 @@ func (b *builtinAesEncryptSig) vecEvalString(ctx EvalContext, input *chunk.Chunk
 	}
 
 	isWarning := !b.ivRequired && len(b.args) == 3
-	isConst := b.args[1].ConstItem(ctx.GetSessionVars().StmtCtx)
+	isConst := b.args[1].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache)
 	var key []byte
 	if isConst {
 		key = encrypt.DeriveKeyMySQL(keyBuf.GetBytes(0), b.keySize)

pkg/expression/builtin_func_param.go

@@ -79,7 +79,7 @@ func buildStringParam(ctx EvalContext, bf *baseBuiltinFunc, idx int, input *chun
 	}
 
 	// Check if this is a const value
-	if bf.args[idx].ConstItem(ctx.GetSessionVars().StmtCtx) {
+	if bf.args[idx].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) {
 		// Initialize the const
 		var isConstNull bool
 		pa.defaultStrVal, isConstNull, err = bf.args[idx].EvalString(ctx, chunk.Row{})
@@ -111,7 +111,7 @@ func buildIntParam(ctx EvalContext, bf *baseBuiltinFunc, idx int, input *chunk.C
 	}
 
 	// Check if this is a const value
-	if bf.args[idx].ConstItem(ctx.GetSessionVars().StmtCtx) {
+	if bf.args[idx].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) {
 		// Initialize the const
 		var isConstNull bool
 		pa.defaultIntVal, isConstNull, err = bf.args[idx].EvalInt(ctx, chunk.Row{})

pkg/expression/builtin_ilike.go

@@ -102,7 +102,7 @@ func (b *builtinIlikeSig) evalInt(ctx EvalContext, row chunk.Row) (int64, bool,
 	memorization := func() {
 		if b.pattern == nil {
 			b.pattern = collate.ConvertAndGetBinCollation(b.collation).Pattern()
-			if b.args[1].ConstItem(ctx.GetSessionVars().StmtCtx) && b.args[2].ConstItem(ctx.GetSessionVars().StmtCtx) {
+			if b.args[1].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) && b.args[2].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) {
 				b.pattern.Compile(patternStr, byte(escape))
 				b.isMemorizedPattern = true
 			}

pkg/expression/builtin_ilike_vec.go

@@ -73,7 +73,7 @@ func (b *builtinIlikeSig) getEscape(ctx EvalContext, input *chunk.Chunk, result
 	rowNum := input.NumRows()
 	escape := int64('\\')
 
-	if !b.args[2].ConstItem(ctx.GetSessionVars().StmtCtx) {
+	if !b.args[2].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) {
 		return escape, true, errors.Errorf("escape should be const")
 	}
 

pkg/expression/builtin_like.go

@@ -87,7 +87,7 @@ func (b *builtinLikeSig) evalInt(ctx EvalContext, row chunk.Row) (int64, bool, e
 	memorization := func() {
 		if b.pattern == nil {
 			b.pattern = b.collator().Pattern()
-			if b.args[1].ConstItem(ctx.GetSessionVars().StmtCtx) && b.args[2].ConstItem(ctx.GetSessionVars().StmtCtx) {
+			if b.args[1].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) && b.args[2].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) {
 				b.pattern.Compile(patternStr, byte(escape))
 				b.isMemorizedPattern = true
 			}

pkg/expression/builtin_other.go

@@ -197,7 +197,7 @@ func (b *builtinInIntSig) buildHashMapForConstArgs(ctx sessionctx.Context) error
 	b.nonConstArgsIdx = make([]int, 0)
 	b.hashSet = make(map[int64]bool, len(b.args)-1)
 	for i := 1; i < len(b.args); i++ {
-		if b.args[i].ConstItem(ctx.GetSessionVars().StmtCtx) {
+		if b.args[i].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) {
 			val, isNull, err := b.args[i].EvalInt(ctx, chunk.Row{})
 			if err != nil {
 				return err
@@ -290,7 +290,7 @@ func (b *builtinInStringSig) buildHashMapForConstArgs(ctx sessionctx.Context) er
 	b.hashSet = set.NewStringSet()
 	collator := collate.GetCollator(b.collation)
 	for i := 1; i < len(b.args); i++ {
-		if b.args[i].ConstItem(ctx.GetSessionVars().StmtCtx) {
+		if b.args[i].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) {
 			val, isNull, err := b.args[i].EvalString(ctx, chunk.Row{})
 			if err != nil {
 				return err
@@ -363,7 +363,7 @@ func (b *builtinInRealSig) buildHashMapForConstArgs(ctx sessionctx.Context) erro
 	b.nonConstArgsIdx = make([]int, 0)
 	b.hashSet = set.NewFloat64Set()
 	for i := 1; i < len(b.args); i++ {
-		if b.args[i].ConstItem(ctx.GetSessionVars().StmtCtx) {
+		if b.args[i].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) {
 			val, isNull, err := b.args[i].EvalReal(ctx, chunk.Row{})
 			if err != nil {
 				return err
@@ -434,7 +434,7 @@ func (b *builtinInDecimalSig) buildHashMapForConstArgs(ctx sessionctx.Context) e
 	b.nonConstArgsIdx = make([]int, 0)
 	b.hashSet = set.NewStringSet()
 	for i := 1; i < len(b.args); i++ {
-		if b.args[i].ConstItem(ctx.GetSessionVars().StmtCtx) {
+		if b.args[i].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) {
 			val, isNull, err := b.args[i].EvalDecimal(ctx, chunk.Row{})
 			if err != nil {
 				return err
@@ -514,7 +514,7 @@ func (b *builtinInTimeSig) buildHashMapForConstArgs(ctx sessionctx.Context) erro
 	b.nonConstArgsIdx = make([]int, 0)
 	b.hashSet = make(map[types.CoreTime]struct{}, len(b.args)-1)
 	for i := 1; i < len(b.args); i++ {
-		if b.args[i].ConstItem(ctx.GetSessionVars().StmtCtx) {
+		if b.args[i].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) {
 			val, isNull, err := b.args[i].EvalTime(ctx, chunk.Row{})
 			if err != nil {
 				return err
@@ -585,7 +585,7 @@ func (b *builtinInDurationSig) buildHashMapForConstArgs(ctx sessionctx.Context)
 	b.nonConstArgsIdx = make([]int, 0)
 	b.hashSet = make(map[time.Duration]struct{}, len(b.args)-1)
 	for i := 1; i < len(b.args); i++ {
-		if b.args[i].ConstItem(ctx.GetSessionVars().StmtCtx) {
+		if b.args[i].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) {
 			val, isNull, err := b.args[i].EvalDuration(ctx, chunk.Row{})
 			if err != nil {
 				return err

pkg/expression/builtin_regexp.go

@@ -165,7 +165,7 @@ func (re *regexpBaseFuncSig) genRegexp(pat string, matchType string) (*regexp.Re
 //
 // return true: need, false: needless
 func (re *regexpBaseFuncSig) canMemorize(ctx EvalContext, matchTypeIdx int) bool {
-	return re.args[patternIdx].ConstItem(ctx.GetSessionVars().StmtCtx) && (len(re.args) <= matchTypeIdx || re.args[matchTypeIdx].ConstItem(ctx.GetSessionVars().StmtCtx))
+	return re.args[patternIdx].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache) && (len(re.args) <= matchTypeIdx || re.args[matchTypeIdx].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache))
 }
 
 func (re *regexpBaseFuncSig) initMemoizedRegexp(params []*funcParam, matchTypeIdx int) error {
@@ -1251,7 +1251,7 @@ func getInstructions(repl []byte) ([]Instruction, error) {
 }
 
 func (re *builtinRegexpReplaceFuncSig) canInstructionsMemorized(ctx EvalContext) bool {
-	return re.args[replacementIdx].ConstItem(ctx.GetSessionVars().StmtCtx)
+	return re.args[replacementIdx].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache)
 }
 
 func (re *builtinRegexpReplaceFuncSig) evalString(ctx EvalContext, row chunk.Row) (string, bool, error) {
@@ -1473,7 +1473,7 @@ func (re *builtinRegexpReplaceFuncSig) vecEvalString(ctx EvalContext, input *chu
 	buffers := getBuffers(params)
 
 	instructions := make([]Instruction, 0)
-	isReplConst := re.baseBuiltinFunc.args[2].ConstItem(ctx.GetSessionVars().StmtCtx)
+	isReplConst := re.baseBuiltinFunc.args[2].ConstItem(ctx.GetSessionVars().StmtCtx.UseCache)
 	if isReplConst {
 		// repl is const
 		instructions, err = getInstructions([]byte(params[2].getStringVal(0)))

pkg/expression/column.go

@@ -26,7 +26,6 @@ import (
 	"github.com/pingcap/tidb/pkg/parser/charset"
 	"github.com/pingcap/tidb/pkg/parser/model"
 	"github.com/pingcap/tidb/pkg/parser/mysql"
-	"github.com/pingcap/tidb/pkg/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/pkg/types"
 	"github.com/pingcap/tidb/pkg/util/chunk"
 	"github.com/pingcap/tidb/pkg/util/codec"
@@ -173,7 +172,7 @@ func (col *CorrelatedColumn) IsCorrelated() bool {
 }
 
 // ConstItem implements Expression interface.
-func (col *CorrelatedColumn) ConstItem(_ *stmtctx.StatementContext) bool {
+func (col *CorrelatedColumn) ConstItem(_ bool) bool {
 	return false
 }
 
@@ -516,7 +515,7 @@ func (col *Column) IsCorrelated() bool {
 }
 
 // ConstItem implements Expression interface.
-func (col *Column) ConstItem(_ *stmtctx.StatementContext) bool {
+func (col *Column) ConstItem(_ bool) bool {
 	return false
 }
 

pkg/expression/column_test.go

@@ -47,7 +47,7 @@ func TestColumn(t *testing.T) {
 	require.True(t, corCol.EqualColumn(corCol))
 	require.False(t, corCol.EqualColumn(invalidCorCol))
 	require.True(t, corCol.IsCorrelated())
-	require.False(t, corCol.ConstItem(nil))
+	require.False(t, corCol.ConstItem(false))
 	require.True(t, col.EqualColumn(corCol.Decorrelate(schema)))
 	require.True(t, invalidCorCol.EqualColumn(invalidCorCol.Decorrelate(schema)))
 

pkg/expression/constant.go

@@ -20,7 +20,6 @@ import (
 
 	"github.com/pingcap/tidb/pkg/parser/mysql"
 	"github.com/pingcap/tidb/pkg/sessionctx"
-	"github.com/pingcap/tidb/pkg/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/pkg/types"
 	"github.com/pingcap/tidb/pkg/util/chunk"
 	"github.com/pingcap/tidb/pkg/util/codec"
@@ -423,8 +422,8 @@ func (c *Constant) IsCorrelated() bool {
 }
 
 // ConstItem implements Expression interface.
-func (c *Constant) ConstItem(sc *stmtctx.StatementContext) bool {
-	return !sc.UseCache || (c.DeferredExpr == nil && c.ParamMarker == nil)
+func (c *Constant) ConstItem(acrossCtx bool) bool {
+	return !acrossCtx || (c.DeferredExpr == nil && c.ParamMarker == nil)
 }
 
 // Decorrelate implements Expression interface.

pkg/expression/constant_propagation.go

@@ -56,7 +56,7 @@ func (s *basePropConstSolver) insertCol(col *Column) {
 // tryToUpdateEQList tries to update the eqList. When the eqList has store this column with a different constant, like
 // a = 1 and a = 2, we set the second return value to false.
 func (s *basePropConstSolver) tryToUpdateEQList(col *Column, con *Constant) (bool, bool) {
-	if con.ConstItem(s.ctx.GetSessionVars().StmtCtx) && con.Value.IsNull() {
+	if con.ConstItem(s.ctx.GetSessionVars().StmtCtx.UseCache) && con.Value.IsNull() {
 		return false, true
 	}
 	id := s.getColID(col)

pkg/expression/expression.go

@@ -140,14 +140,16 @@ type Expression interface {
 	IsCorrelated() bool
 
 	// ConstItem checks if this expression is constant item, regardless of query evaluation state.
+	// If the argument `acrossCtxs` is true,
+	// it will check if this expression returns a constant value even across multiple contexts.
 	// An expression is constant item if it:
 	// refers no tables.
 	// refers no correlated column.
 	// refers no subqueries that refers any tables.
 	// refers no non-deterministic functions.
 	// refers no statement parameters.
 	// refers no param markers when prepare plan cache is enabled.
-	ConstItem(sc *stmtctx.StatementContext) bool
+	ConstItem(acrossCtx bool) bool
 
 	// Decorrelate try to decorrelate the expression by schema.
 	Decorrelate(schema *Schema) Expression

pkg/expression/expression_test.go

@@ -108,7 +108,7 @@ func TestConstant(t *testing.T) {
 	ctx := createContext(t)
 	sc := stmtctx.NewStmtCtxWithTimeZone(time.Local)
 	require.False(t, NewZero().IsCorrelated())
-	require.True(t, NewZero().ConstItem(sc))
+	require.True(t, NewZero().ConstItem(sc.UseCache))
 	require.True(t, NewZero().Decorrelate(nil).Equal(ctx, NewZero()))
 	require.Equal(t, []byte{0x0, 0x8, 0x0}, NewZero().HashCode())
 	require.False(t, NewZero().Equal(ctx, NewOne()))
@@ -136,13 +136,13 @@ func TestIsBinaryLiteral(t *testing.T) {
 func TestConstItem(t *testing.T) {
 	ctx := createContext(t)
 	sf := newFunctionWithMockCtx(ast.Rand)
-	require.False(t, sf.ConstItem(ctx.GetSessionVars().StmtCtx))
+	require.False(t, sf.ConstItem(ctx.GetSessionVars().StmtCtx.UseCache))
 	sf = newFunctionWithMockCtx(ast.UUID)
-	require.False(t, sf.ConstItem(ctx.GetSessionVars().StmtCtx))
+	require.False(t, sf.ConstItem(ctx.GetSessionVars().StmtCtx.UseCache))
 	sf = newFunctionWithMockCtx(ast.GetParam, NewOne())
-	require.False(t, sf.ConstItem(ctx.GetSessionVars().StmtCtx))
+	require.False(t, sf.ConstItem(ctx.GetSessionVars().StmtCtx.UseCache))
 	sf = newFunctionWithMockCtx(ast.Abs, NewOne())
-	require.True(t, sf.ConstItem(ctx.GetSessionVars().StmtCtx))
+	require.True(t, sf.ConstItem(ctx.GetSessionVars().StmtCtx.UseCache))
 }
 
 func TestVectorizable(t *testing.T) {

pkg/expression/scalar_function.go

@@ -26,7 +26,6 @@ import (
 	"github.com/pingcap/tidb/pkg/parser/mysql"
 	"github.com/pingcap/tidb/pkg/parser/terror"
 	"github.com/pingcap/tidb/pkg/sessionctx"
-	"github.com/pingcap/tidb/pkg/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/pkg/sessionctx/variable"
 	"github.com/pingcap/tidb/pkg/types"
 	"github.com/pingcap/tidb/pkg/util/chunk"
@@ -350,13 +349,13 @@ func (sf *ScalarFunction) IsCorrelated() bool {
 }
 
 // ConstItem implements Expression interface.
-func (sf *ScalarFunction) ConstItem(sc *stmtctx.StatementContext) bool {
+func (sf *ScalarFunction) ConstItem(acrossCtx bool) bool {
 	// Note: some unfoldable functions are deterministic, we use unFoldableFunctions here for simplification.
 	if _, ok := unFoldableFunctions[sf.FuncName.L]; ok {
 		return false
 	}
 	for _, arg := range sf.GetArgs() {
-		if !arg.ConstItem(sc) {
+		if !arg.ConstItem(acrossCtx) {
 			return false
 		}
 	}

pkg/expression/scalar_function_test.go

@@ -102,7 +102,7 @@ func TestScalarFunction(t *testing.T) {
 	require.NoError(t, err)
 	require.EqualValues(t, []byte{0x22, 0x6c, 0x74, 0x28, 0x43, 0x6f, 0x6c, 0x75, 0x6d, 0x6e, 0x23, 0x31, 0x2c, 0x20, 0x31, 0x29, 0x22}, res)
 	require.False(t, sf.IsCorrelated())
-	require.False(t, sf.ConstItem(ctx.GetSessionVars().StmtCtx))
+	require.False(t, sf.ConstItem(ctx.GetSessionVars().StmtCtx.UseCache))
 	require.True(t, sf.Decorrelate(nil).Equal(ctx, sf))
 	require.EqualValues(t, []byte{0x3, 0x4, 0x6c, 0x74, 0x1, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x5, 0xbf, 0xf0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, sf.HashCode())
 

pkg/expression/util_test.go

@@ -571,7 +571,7 @@ func (m *MockExpr) GetType() *types.FieldType                         { return m
 func (m *MockExpr) Clone() Expression                                 { return nil }
 func (m *MockExpr) Equal(ctx EvalContext, e Expression) bool          { return false }
 func (m *MockExpr) IsCorrelated() bool                                { return false }
-func (m *MockExpr) ConstItem(_ *stmtctx.StatementContext) bool        { return false }
+func (m *MockExpr) ConstItem(_ bool) bool                             { return false }
 func (m *MockExpr) Decorrelate(schema *Schema) Expression             { return m }
 func (m *MockExpr) ResolveIndices(schema *Schema) (Expression, error) { return m, nil }
 func (m *MockExpr) resolveIndices(schema *Schema) error               { return nil }