always push isnull to block filters (matrixorigin#16851)

always push isnull to block filters Approved by: @aunjgr
socekin · Jun 14, 2024 · 16a2113 · 16a2113
1 parent 7ced499
commit 16a2113
Showing 1 changed file with 7 additions and 2 deletions.
diff --git a/pkg/sql/plan/stats.go b/pkg/sql/plan/stats.go
@@ -595,7 +595,7 @@ func estimateFilterBlockSelectivity(ctx context.Context, expr *plan.Expr, tableD
 	}
 	col := extractColRefInFilter(expr)
 	if col != nil {
-		blocksel := calcBlockSelectivityUsingShuffleRange(s.ShuffleRangeMap[col.Name], expr.Selectivity)
+		blocksel := calcBlockSelectivityUsingShuffleRange(s.ShuffleRangeMap[col.Name], expr)
 		switch GetSortOrder(tableDef, col.ColPos) {
 		case 0:
 			blocksel = math.Min(blocksel, 0.2)
@@ -1341,8 +1341,13 @@ func DeepCopyStats(stats *plan.Stats) *plan.Stats {
 	}
 }
 
-func calcBlockSelectivityUsingShuffleRange(s *pb.ShuffleRange, sel float64) float64 {
+func calcBlockSelectivityUsingShuffleRange(s *pb.ShuffleRange, expr *plan.Expr) float64 {
+	sel := expr.Selectivity
 	if s == nil {
+		if expr.GetF().Func.ObjName == "isnull" || expr.GetF().Func.ObjName == "is_null" {
+			//speicial handle for isnull
+			return sel
+		}
 		if sel <= 0.01 {
 			return sel * 100
 		} else {