From 6a468c343b31aabead7d3a5e11079bfcddbfd667 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Thu, 9 Mar 2017 12:13:48 -0500
Subject: [PATCH] Fix bug in parallel tidbitmap iteration.
Avoid computing idxpages[istate->spageptr] until after checking
that istate->spageptr is a legal index.
Dilip Kumar, per a report from David Rowley
Discussion: http://postgr.es/m/CAKJS1f8OtrHE+-P+=E=4ycnL29e9idZKuaTQ6o2MbhvGN9D8ig@mail.gmail.com
---
src/backend/nodes/tidbitmap.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/src/backend/nodes/tidbitmap.c b/src/backend/nodes/tidbitmap.c
index 44cc9daa03f..8e915646d93 100644
--- a/src/backend/nodes/tidbitmap.c
+++ b/src/backend/nodes/tidbitmap.c
@@ -1103,13 +1103,12 @@ tbm_shared_iterate(TBMSharedIterator *iterator)
if (istate->schunkptr < istate->nchunks)
{
PagetableEntry *chunk = &ptbase[idxchunks[istate->schunkptr]];
- PagetableEntry *page = &ptbase[idxpages[istate->spageptr]];
BlockNumber chunk_blockno;
chunk_blockno = chunk->blockno + istate->schunkbit;
if (istate->spageptr >= istate->npages ||
- chunk_blockno < page->blockno)
+ chunk_blockno < ptbase[idxpages[istate->spageptr]].blockno)
{
/* Return a lossy page indicator from the chunk */
output->blockno = chunk_blockno;
--
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