diff --git a/pkg/container/vector/vector.go b/pkg/container/vector/vector.go
index 39e839af4538..79e2d729230d 100644
--- a/pkg/container/vector/vector.go
+++ b/pkg/container/vector/vector.go
@@ -778,26 +778,11 @@ func (v *Vector) UnmarshalBinaryWithCopy(data []byte, mp *mpool.MPool) error {
 	return nil
 }
 
-func (v *Vector) ToConst(row, length int, mp *mpool.MPool) *Vector {
-	w := NewConstNull(v.typ, length, mp)
-	if v.IsConstNull() || v.nsp.Contains(uint64(row)) {
-		return w
+func (v *Vector) ToConst() {
+	if v.nsp.Contains(0) {
+		v.data = v.data[:0]
 	}
-
-	if v.IsConst() {
-		row = 0
-	}
-
-	sz := v.typ.TypeSize()
-	w.data = v.data[row*sz : (row+1)*sz]
-	w.setupFromData()
-	if v.typ.IsVarlen() {
-		w.area = v.area
-	}
-	w.cantFreeData = true
-	w.cantFreeArea = true
-
-	return w
+	v.class = CONSTANT
 }
 
 // PreExtend use to expand the capacity of the vector
diff --git a/pkg/sql/colexec/debugTools.go b/pkg/sql/colexec/debugTools.go
index bbb949a2d3f9..13586fd192d6 100644
--- a/pkg/sql/colexec/debugTools.go
+++ b/pkg/sql/colexec/debugTools.go
@@ -135,14 +135,6 @@ func printFunctionExpressionExecutor(buffer *bytes.Buffer, expr *FunctionExpress
 
 	buffer.WriteString(fmt.Sprintf("%s    needFoldingCheck: %v\n", prefix, expr.folded.needFoldingCheck))
 	buffer.WriteString(fmt.Sprintf("%s    canFold: %v\n", prefix, expr.folded.canFold))
-	if expr.folded.foldVector != nil {
-		if expr.folded.foldVector.GetType() != nil {
-			buffer.WriteString(fmt.Sprintf("%s    foldVector.typ: %s\n", prefix, expr.folded.foldVector.GetType().String()))
-		}
-		buffer.WriteString(fmt.Sprintf("%s    foldVector.value: %s\n", prefix, expr.folded.foldVector.String()))
-	} else {
-		buffer.WriteString(fmt.Sprintf("%s    foldVector is nil\n", prefix))
-	}
 
 	// selectList1, selectList2
 	buffer.WriteString(fmt.Sprintf("%s  selectList1: %v\n", prefix, expr.selectList1))
diff --git a/pkg/sql/colexec/evalExpression.go b/pkg/sql/colexec/evalExpression.go
index 23971707b0f3..ca8e844d64f3 100644
--- a/pkg/sql/colexec/evalExpression.go
+++ b/pkg/sql/colexec/evalExpression.go
@@ -271,6 +271,12 @@ type ParamExpressionExecutor struct {
 }
 
 func (expr *ParamExpressionExecutor) Eval(proc *process.Process, _ []*batch.Batch, _ []bool) (*vector.Vector, error) {
+	if expr.vec != nil {
+		return expr.vec, nil
+	}
+	if expr.null != nil {
+		return expr.null, nil
+	}
 	val, err := proc.GetPrepareParamsAt(expr.pos)
 	if err != nil {
 		return nil, err
@@ -644,7 +650,6 @@ func (expr *FunctionExpressionExecutor) Free() {
 		expr.resultVector.Free()
 		expr.resultVector = nil
 	}
-	expr.folded.reset(expr.m)
 
 	for _, p := range expr.parameterExecutor {
 		if p != nil {
diff --git a/pkg/sql/colexec/evalExpressionOpt.go b/pkg/sql/colexec/evalExpressionOpt.go
index 5fc6750d7fe6..5039b3c5fd5e 100644
--- a/pkg/sql/colexec/evalExpressionOpt.go
+++ b/pkg/sql/colexec/evalExpressionOpt.go
@@ -100,7 +100,6 @@ func modifyResultOwnerToOuter(executor ExpressionExecutor) (succeed bool) {
 	// function expression.
 	if f, ok := executor.(*FunctionExpressionExecutor); ok {
 		f.resultVector = nil
-		f.folded.foldVector = nil
 		return true
 	}
 
diff --git a/pkg/sql/colexec/evalExpressionReset.go b/pkg/sql/colexec/evalExpressionReset.go
index 64251089ad52..055c7188b635 100644
--- a/pkg/sql/colexec/evalExpressionReset.go
+++ b/pkg/sql/colexec/evalExpressionReset.go
@@ -34,16 +34,11 @@ func (expr *FixedVectorExpressionExecutor) ResetForNextQuery() {
 type functionFolding struct {
 	needFoldingCheck bool
 	canFold          bool
-	foldVector       *vector.Vector
 }
 
-func (fF *functionFolding) reset(m *mpool.MPool) {
-	if fF.foldVector != nil {
-		fF.foldVector.Free(m)
-	}
+func (fF *functionFolding) reset(_ *mpool.MPool) {
 	fF.needFoldingCheck = true
 	fF.canFold = false
-	fF.foldVector = nil
 }
 
 type functionInformationForEval struct {
@@ -100,10 +95,11 @@ func (expr *FunctionExpressionExecutor) ResetForNextQuery() {
 }
 
 func (expr *FunctionExpressionExecutor) getFoldedVector(requiredLength int) *vector.Vector {
-	if expr.folded.foldVector.IsConst() {
-		expr.folded.foldVector.SetLength(requiredLength)
+	rv := expr.resultVector.GetResultVector()
+	if rv.IsConst() {
+		rv.SetLength(requiredLength)
 	}
-	return expr.folded.foldVector
+	return rv
 }
 
 func (expr *FunctionExpressionExecutor) doFold(proc *process.Process, atRuntime bool) (err error) {
@@ -163,34 +159,29 @@ func (expr *FunctionExpressionExecutor) doFold(proc *process.Process, atRuntime
 	}
 
 	// fold the function.
-	if execLen > 1 {
-		if err = expr.resultVector.PreExtendAndReset(execLen); err != nil {
-			return err
-		}
-		if err = expr.evalFn(expr.parameterResults, expr.resultVector, proc, execLen, nil); err != nil {
-			return err
-		}
-		expr.folded.foldVector = expr.resultVector.GetResultVector()
-		expr.resultVector.SetResultVector(nil)
-
-	} else {
-		if err = expr.resultVector.PreExtendAndReset(1); err != nil {
-			return err
-		}
-		if err = expr.evalFn(expr.parameterResults, expr.resultVector, proc, 1, nil); err != nil {
-			return err
-		}
-		if expr.folded.foldVector, err = expr.resultVector.GetResultVector().ToConst(0, 1, proc.Mp()).Dup(proc.Mp()); err != nil {
-			return err
-		}
-		expr.resultVector.Free()
+	if err = expr.resultVector.PreExtendAndReset(execLen); err != nil {
+		return err
 	}
+	if err = expr.evalFn(expr.parameterResults, expr.resultVector, proc, execLen, nil); err != nil {
+		return err
+	}
+	if execLen == 1 {
+		expr.resultVector.GetResultVector().ToConst()
+	}
+
 	expr.folded.canFold = true
 	return nil
 }
 
 func (expr *ParamExpressionExecutor) ResetForNextQuery() {
-	// do nothing.
+	if expr.null != nil {
+		expr.null.Free(expr.mp)
+		expr.null = nil
+	}
+	if expr.vec != nil {
+		expr.vec.Free(expr.mp)
+		expr.vec = nil
+	}
 }
 
 func (expr *VarExpressionExecutor) ResetForNextQuery() {
diff --git a/pkg/sql/plan/function/function.go b/pkg/sql/plan/function/function.go
index 72d199df3c20..1ac7d7ac4c48 100644
--- a/pkg/sql/plan/function/function.go
+++ b/pkg/sql/plan/function/function.go
@@ -225,14 +225,8 @@ func RunFunctionDirectly(proc *process.Process, overloadID int64, inputs []*vect
 
 	vec := result.GetResultVector()
 	if fold {
-		// ToConst is a confused method. it just returns a new pointer to the same memory.
-		// so we need to duplicate it.
-		cvec, er := vec.ToConst(0, length, mp).Dup(mp)
-		result.Free()
-		if er != nil {
-			return nil, er
-		}
-		return cvec, nil
+		vec.ToConst()
+		vec.SetLength(length)
 	}
 	return vec, nil
 }