diff --git a/pkg/expression/builtin_miscellaneous_vec.go b/pkg/expression/builtin_miscellaneous_vec.go
index 1c1c584049..2be48400fa 100644
--- a/pkg/expression/builtin_miscellaneous_vec.go
+++ b/pkg/expression/builtin_miscellaneous_vec.go
@@ -30,6 +30,11 @@ import (
 	"github.com/pingcap/tidb/pkg/util/vitess"
 )
 
+// UUIDStrLen is the length of a UUID in string format
+// 16 bytes in hex is 32 characters, plus 4 hyphens = 36 characters (hex/ASCII, 1 byte chars)
+// https://datatracker.ietf.org/doc/html/rfc9562#name-uuid-format
+const UUIDStrLen = 36
+
 func (b *builtinInetNtoaSig) vecEvalString(ctx EvalContext, input *chunk.Chunk, result *chunk.Column) error {
 	n := input.NumRows()
 	buf, err := b.bufAllocator.get()
@@ -207,7 +212,7 @@ func (b *builtinUUIDSig) vectorized() bool {
 
 func (b *builtinUUIDSig) vecEvalString(ctx EvalContext, input *chunk.Chunk, result *chunk.Column) error {
 	n := input.NumRows()
-	result.ReserveString(n)
+	result.ReserveStringWithSizeHint(n, UUIDStrLen)
 	var id uuid.UUID
 	var err error
 	for range n {
@@ -226,7 +231,7 @@ func (b *builtinUUIDv4Sig) vectorized() bool {
 
 func (b *builtinUUIDv4Sig) vecEvalString(ctx EvalContext, input *chunk.Chunk, result *chunk.Column) error {
 	n := input.NumRows()
-	result.ReserveString(n)
+	result.ReserveStringWithSizeHint(n, UUIDStrLen)
 	var id uuid.UUID
 	var err error
 	for range n {
@@ -245,7 +250,7 @@ func (b *builtinUUIDv7Sig) vectorized() bool {
 
 func (b *builtinUUIDv7Sig) vecEvalString(ctx EvalContext, input *chunk.Chunk, result *chunk.Column) error {
 	n := input.NumRows()
-	result.ReserveString(n)
+	result.ReserveStringWithSizeHint(n, UUIDStrLen)
 	var id uuid.UUID
 	var err error
 	for range n {
diff --git a/pkg/util/chunk/column.go b/pkg/util/chunk/column.go
index 857c5fc3ca..ef3f1bc4fa 100644
--- a/pkg/util/chunk/column.go
+++ b/pkg/util/chunk/column.go
@@ -612,6 +612,12 @@ func (c *Column) ReserveString(n int) {
 	c.reserve(n, 8)
 }
 
+// ReserveStringWithSizeHint changes the column capacity to store n strings of a predetermined size.
+// example: a 36 character text format UUID: ReserveStringWithSizeHint(1, 36) for a single entry.
+func (c *Column) ReserveStringWithSizeHint(n int, size int) {
+	c.reserve(n, size)
+}
+
 // ReserveBytes changes the column capacity to store n bytes elements and set the length to zero.
 func (c *Column) ReserveBytes(n int) {
 	c.reserve(n, 8)