statistics: fix unnecessary index fmsketch loading (#42074)

close #42052
pingcap · Mar 10, 2023 · cdab358 · cdab358
1 parent a273039
commit cdab358
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Showing 2 changed files with 34 additions and 5 deletions.
diff --git a/statistics/integration_test.go b/statistics/integration_test.go
@@ -719,3 +719,27 @@ func TestColumnStatsLazyLoad(t *testing.T) {
 	require.True(t, h.GetTableStats(tblInfo).Columns[c1.ID].IsAllEvicted())
 	require.True(t, h.GetTableStats(tblInfo).Columns[c2.ID].IsAllEvicted())
 }
+
+func TestUpdateNotLoadIndexFMSketch(t *testing.T) {
+	store, dom := testkit.CreateMockStoreAndDomain(t)
+	tk := testkit.NewTestKit(t, store)
+	h := dom.StatsHandle()
+	tk.MustExec("use test")
+	tk.MustExec("create table t(a int, b int, index idx(a)) partition by range (a) (partition p0 values less than (10),partition p1 values less than maxvalue)")
+	tk.MustExec("insert into t values (1,2), (3,4), (5,6), (7,8)")
+	require.NoError(t, h.HandleDDLEvent(<-h.DDLEventCh()))
+	tk.MustExec("analyze table t")
+	is := dom.InfoSchema()
+	tbl, err := is.TableByName(model.NewCIStr("test"), model.NewCIStr("t"))
+	require.NoError(t, err)
+	tblInfo := tbl.Meta()
+	idxInfo := tblInfo.Indices[0]
+	p0 := tblInfo.Partition.Definitions[0]
+	p1 := tblInfo.Partition.Definitions[1]
+	require.Nil(t, h.GetPartitionStats(tblInfo, p0.ID).Indices[idxInfo.ID].FMSketch)
+	require.Nil(t, h.GetPartitionStats(tblInfo, p1.ID).Indices[idxInfo.ID].FMSketch)
+	h.Clear()
+	require.NoError(t, h.Update(is))
+	require.Nil(t, h.GetPartitionStats(tblInfo, p0.ID).Indices[idxInfo.ID].FMSketch)
+	require.Nil(t, h.GetPartitionStats(tblInfo, p1.ID).Indices[idxInfo.ID].FMSketch)
+}
diff --git a/statistics/interact_with_storage.go b/statistics/interact_with_storage.go
@@ -253,7 +253,7 @@ func ExtendedStatsFromStorage(reader *StatsReader, table *Table, physicalID int6
 	return table, nil
 }
 
-func indexStatsFromStorage(reader *StatsReader, row chunk.Row, table *Table, tableInfo *model.TableInfo) error {
+func indexStatsFromStorage(reader *StatsReader, row chunk.Row, table *Table, tableInfo *model.TableInfo, loadAll bool) error {
 	histID := row.GetInt64(2)
 	distinct := row.GetInt64(3)
 	histVer := row.GetUint64(4)
@@ -279,9 +279,14 @@ func indexStatsFromStorage(reader *StatsReader, row chunk.Row, table *Table, tab
 			if err != nil {
 				return errors.Trace(err)
 			}
-			fmSketch, err := FMSketchFromStorage(reader, table.PhysicalID, 1, histID)
-			if err != nil {
-				return errors.Trace(err)
+			var fmSketch *FMSketch
+			if loadAll {
+				// FMSketch is only used when merging partition stats into global stats. When merging partition stats into global stats,
+				// we load all the statistics, i.e., loadAll is true.
+				fmSketch, err = FMSketchFromStorage(reader, table.PhysicalID, 1, histID)
+				if err != nil {
+					return errors.Trace(err)
+				}
 			}
 			idx = &Index{
 				Histogram:  *hg,
@@ -467,7 +472,7 @@ func TableStatsFromStorage(reader *StatsReader, tableInfo *model.TableInfo, phys
 	}
 	for _, row := range rows {
 		if row.GetInt64(1) > 0 {
-			err = indexStatsFromStorage(reader, row, table, tableInfo)
+			err = indexStatsFromStorage(reader, row, table, tableInfo, loadAll)
 		} else {
 			err = columnStatsFromStorage(reader, row, table, tableInfo, loadAll, lease)
 		}