statistics: fix Clone method to include checked field in ColAndIdxExistenceMap (#60171)

close #60104

Author: 0xPoe

pkg/statistics/BUILD.bazel

@@ -79,11 +79,12 @@ go_test(
         "sample_test.go",
         "scalar_test.go",
         "statistics_test.go",
+        "table_test.go",
     ],
     data = glob(["testdata/**"]),
     embed = [":statistics"],
     flaky = True,
-    shard_count = 37,
+    shard_count = 38,
     deps = [
         "//pkg/config",
         "//pkg/meta/model",

pkg/statistics/table.go

@@ -163,6 +163,7 @@ func (m *ColAndIdxExistenceMap) ColNum() int {
 // Clone deeply copies the map.
 func (m *ColAndIdxExistenceMap) Clone() *ColAndIdxExistenceMap {
 	mm := NewColAndIndexExistenceMap(len(m.colAnalyzed), len(m.idxAnalyzed))
+	mm.checked = m.checked
 	mm.colAnalyzed = maps.Clone(m.colAnalyzed)
 	mm.idxAnalyzed = maps.Clone(m.idxAnalyzed)
 	return mm

pkg/statistics/table_test.go

@@ -0,0 +1,31 @@
+// Copyright 2025 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package statistics
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestCloneColAndIdxExistenceMap(t *testing.T) {
+	m := NewColAndIndexExistenceMapWithoutSize()
+	m.InsertCol(1, true)
+	m.InsertIndex(1, true)
+	m.SetChecked()
+
+	m2 := m.Clone()
+	require.Equal(t, m, m2)
+}