executor: only show valid columns in stats_histogram (pingcap#9487)

eurekaka · Feb 28, 2019 · faf6ed7 · faf6ed7
1 parent 103d3b3
commit faf6ed7
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Showing 3 changed files with 19 additions and 2 deletions.
diff --git a/executor/show_stats.go b/executor/show_stats.go
@@ -54,6 +54,10 @@ func (e *ShowExec) fetchShowStatsHistogram() error {
 			statsTbl := h.GetTableStats(tbl)
 			if !statsTbl.Pseudo {
 				for _, col := range statsTbl.Columns {
+					// Pass a nil StatementContext to avoid column stats being marked as needed.
+					if statsTbl.ColumnIsInvalid(nil, col.ID) {
+						continue
+					}
 					e.histogramToRow(db.Name.O, tbl.Name.O, col.Info.Name.O, 0, col.Histogram, col.AvgColSize(statsTbl.Count))
 				}
 				for _, idx := range statsTbl.Indices {

diff --git a/executor/show_stats_test.go b/executor/show_stats_test.go
@@ -42,13 +42,26 @@ func (s *testSuite) TestShowStatsHistograms(c *C) {
 	tk.MustExec("drop table if exists t")
 	tk.MustExec("create table t (a int, b int)")
 	tk.MustExec("analyze table t")
-	result := tk.MustQuery("show stats_histograms").Sort()
+	result := tk.MustQuery("show stats_histograms")
+	c.Assert(len(result.Rows()), Equals, 0)
+	tk.MustExec("insert into t values(1,1)")
+	tk.MustExec("analyze table t")
+	result = tk.MustQuery("show stats_histograms").Sort()
 	c.Assert(len(result.Rows()), Equals, 2)
 	c.Assert(result.Rows()[0][2], Equals, "a")
 	c.Assert(result.Rows()[1][2], Equals, "b")
 	result = tk.MustQuery("show stats_histograms where column_name = 'a'")
 	c.Assert(len(result.Rows()), Equals, 1)
 	c.Assert(result.Rows()[0][2], Equals, "a")
+
+	tk.MustExec("drop table t")
+	tk.MustExec("create table t(a int, b int, c int, index idx_b(b), index idx_c_a(c, a))")
+	tk.MustExec("insert into t values(1,null,1),(2,null,2),(3,3,3),(4,null,4),(null,null,null)")
+	res := tk.MustQuery("show stats_histograms where table_name = 't'")
+	c.Assert(len(res.Rows()), Equals, 0)
+	tk.MustExec("analyze table t index idx_b")
+	res = tk.MustQuery("show stats_histograms where table_name = 't' and column_name = 'idx_b'")
+	c.Assert(len(res.Rows()), Equals, 1)
 }
 
 func (s *testSuite) TestShowStatsBuckets(c *C) {

diff --git a/statistics/table.go b/statistics/table.go
@@ -349,7 +349,7 @@ func (coll *HistColl) ColumnIsInvalid(sc *stmtctx.StatementContext, colID int64)
 	if !ok || coll.Pseudo && col.NotAccurate() {
 		return true
 	}
-	if col.NDV > 0 && col.Len() == 0 && coll.HavePhysicalID {
+	if col.NDV > 0 && col.Len() == 0 && coll.HavePhysicalID && sc != nil {
 		sc.SetHistogramsNotLoad()
 		histogramNeededColumns.insert(tableColumnID{tableID: coll.PhysicalID, columnID: col.Info.ID})
 	}