check whether the column is generated by projection

pingcap · Jan 30, 2023 · dd9ac2d · dd9ac2d
1 parent 882dea3
commit dd9ac2d
Showing 1 changed file with 6 additions and 3 deletions.
diff --git a/planner/core/rule_topn_push_down.go b/planner/core/rule_topn_push_down.go
@@ -141,9 +141,12 @@ func (p *LogicalProjection) pushDownTopN(topN *LogicalTopN, opt *logicalOptimize
 		for _, by := range topN.ByItems {
 			cols := expression.ExtractColumns(by.Expr)
 			for _, col := range cols {
-				if p.Schema().Contains(col) && col.ID == 0 {
-					p.children[0] = p.children[0].pushDownTopN(nil, opt)
-					return topN.setChild(p, opt)
+				if col.ID == 0 && p.Schema().Contains(col) {
+					if !p.children[0].Schema().Contains(col) {
+						// the column is generated by projection
+						p.children[0] = p.children[0].pushDownTopN(nil, opt)
+						return topN.setChild(p, opt)
+					}
 				}
 			}
 		}