Fix possible crash with Parallel Bitmap Heap Scan.

robertmhaas · robertmhaas · commit 6393613b6a1e · 2017-10-13T15:02:45.000-04:00
If a Parallel Bitmap Heap scan's chain of leftmost descendents includes a BitmapOr whose first child is a BitmapAnd, the prior coding would mistakenly create a non-shared TIDBitmap and then try to perform shared iteration. Report by Tomas Vondra. Patch by Dilip Kumar. Discussion: http://postgr.es/m/50e89684-8ad9-dead-8767-c9545bafd3b6@2ndquadrant.com
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
@@ -4933,7 +4933,11 @@ bitmap_subplan_mark_shared(Plan *plan)
 		bitmap_subplan_mark_shared(
 								   linitial(((BitmapAnd *) plan)->bitmapplans));
 	else if (IsA(plan, BitmapOr))
+	{
 		((BitmapOr *) plan)->isshared = true;
+		bitmap_subplan_mark_shared(
+								   linitial(((BitmapOr *) plan)->bitmapplans));
+	}
 	else if (IsA(plan, BitmapIndexScan))
 		((BitmapIndexScan *) plan)->isshared = true;
 	else
