infoschema: simplify size calculation for array (#58320)

ref #50959

Author: D3Hunter

pkg/infoschema/internal/sizer.go

@@ -41,7 +41,7 @@ func sizeOf(v reflect.Value, cache map[uintptr]bool) int {
 			}
 			sum += s
 		}
-		return sum + (v.Cap()-v.Len())*int(v.Type().Elem().Size())
+		return sum
 	case reflect.Slice:
 		// return 0 if this node has been visited already
 		if cache[v.Pointer()] {

pkg/infoschema/internal/sizer_test.go

@@ -19,6 +19,9 @@ import (
 )
 
 func TestSize(t *testing.T) {
+	stringSlice := make([]string, 2, 5)
+	stringSlice[0] = "AAAAAAAAAA"
+	stringSlice[1] = "BBBBBBBBBBBB"
 	tests := []struct {
 		name string
 		v    any
@@ -29,11 +32,21 @@ func TestSize(t *testing.T) {
 			v:    [3]int32{1, 2, 3}, // 3 * 4  = 12
 			want: 12,
 		},
+		{
+			name: "Array 2",
+			v:    [5]string{}, // 5 * 16  = 80
+			want: 80,
+		},
 		{
 			name: "Slice",
 			v:    make([]int64, 2, 5), // 5 * 8 + 24 = 64
 			want: 64,
 		},
+		{
+			name: "string Slice",
+			v:    stringSlice, // 5 * 16 + 10 + 12 + 24 = 126
+			want: 126,
+		},
 		{
 			name: "String",
 			v:    "ABCdef", // 6 + 16 = 22