When building a bitmap scan, must copy the bitmapqualorig expression tree

to avoid sharing substructure with the lower-level indexquals.  This is
currently only an issue if there are SubPlans in the indexquals, which is
uncommon but not impossible --- see bug #2218 reported by Nicholas Vinen.
We use the same kluge for indexqual vs indexqualorig in the index scans
themselves ... would be nice to clean this up someday.

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 596fb9d7c1d14a3c2c403dd002e1398c6600f485..df0df1da2ab7428fd97baba262401d7dec4bf252 100644 (file)
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -963,6 +963,12 @@ create_bitmap_scan_plan(PlannerInfo *root,
         */
        bitmapqualorig = list_difference_ptr(bitmapqualorig, qpqual);
 
+       /*
+        * Copy the finished bitmapqualorig to make sure we have an independent
+        * copy --- needed in case there are subplans in the index quals
+        */
+       bitmapqualorig = copyObject(bitmapqualorig);
+
        /* Finally ready to build the plan node */
        scan_plan = make_bitmap_heapscan(tlist,
                                                                         qpqual,