This is an automated cherry-pick of pingcap#47268

Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>

pkg/executor/analyze_col_v2.go

@@ -326,6 +326,7 @@ func (e *AnalyzeColumnsExecV2) buildSamplingStats(
 			e.memTracker.Consume(rootRowCollector.Base().MemSize - oldRootCollectorSize - mergeResult.collector.Base().MemSize)
 			mergeResult.collector.DestroyAndPutToPool()
 		}
+<<<<<<< HEAD:pkg/executor/analyze_col_v2.go
 		return err
 	})
 	err = taskEg.Wait()
@@ -335,6 +336,18 @@ func (e *AnalyzeColumnsExecV2) buildSamplingStats(
 			err = stderrors.Join(err, err1)
 		}
 		return 0, nil, nil, nil, nil, getAnalyzePanicErr(err)
+=======
+		oldRootCollectorSize := rootRowCollector.Base().MemSize
+		oldRootCollectorCount := rootRowCollector.Base().Count
+		// Merge the result from sub-collectors.
+		rootRowCollector.MergeCollector(mergeResult.collector)
+		newRootCollectorCount := rootRowCollector.Base().Count
+		printAnalyzeMergeCollectorLog(oldRootCollectorCount, newRootCollectorCount,
+			mergeResult.collector.Base().Count, e.tableID.TableID, e.tableID.PartitionID, e.tableID.IsPartitionTable(),
+			"merge subMergeWorker in AnalyzeColumnsExecV2", -1)
+		e.memTracker.Consume(rootRowCollector.Base().MemSize - oldRootCollectorSize - mergeResult.collector.Base().MemSize)
+		mergeResult.collector.DestroyAndPutToPool()
+>>>>>>> 62a048c92c7 (executor: reuse fm sketch when to analyze (#47268)):executor/analyze_col_v2.go
 	}
 	err = mergeEg.Wait()
 	defer e.memTracker.Release(rootRowCollector.Base().MemSize)

pkg/statistics/fmsketch.go

@@ -213,7 +213,16 @@ func (s *FMSketch) MemoryUsage() (sum int64) {
 }
 
 func (s *FMSketch) reset() {
-	s.hashset.Clear()
+	// not use hashset.Clear, it will release all memory and Not conducive to memory reuse.
+	// the size of set is not more than 10000.
+	set := make([]uint64, 0, s.hashset.Count())
+	s.hashset.Iter(func(k uint64, v bool) (stop bool) {
+		set = append(set, k)
+		return false
+	})
+	for _, k := range set {
+		s.hashset.Delete(k)
+	}
 	s.mask = 0
 	s.maxSize = 0
 }