Fix possible crash with Parallel Bitmap Heap Scan.

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
index 792ea84a81854ddf83e4ea171d321d71e9382b91..c802d61c39e3290a024eedd3d9ca787bc1a35854 100644 (file)
--- 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