From e42b3c3bd6a9c6233ac4c8a2e9b040367ba2f97c Mon Sep 17 00:00:00 2001
From: Peter Geoghegan <pg@bowt.ie>
Date: Tue, 26 Jan 2021 23:24:37 -0800
Subject: [PATCH] Fix GiST index deletion assert issue.
Avoid calling heap_index_delete_tuples() with an empty deltids array to
avoid an assertion failure.
This issue was arguably an oversight in commit b5f58cf2, though the
failing assert itself was added by my recent commit d168b666. No
backpatch, though, since the oversight is harmless in the back branches.
Author: Peter Geoghegan <pg@bowt.ie>
Reported-By: Jaime Casanova <jcasanov@systemguards.com.ec>
Discussion: https://postgr.es/m/CAJKUy5jscES84n3puE=sYngyF+zpb4wv8UMtuLnLPv5z=6yyNw@mail.gmail.com
---
src/backend/access/gist/gist.c | 13 +++++++------
src/backend/access/index/genam.c | 2 ++
2 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index f203bb594cd..0683f42c258 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -1645,7 +1645,6 @@ gistprunepage(Relation rel, Page page, Buffer buffer, Relation heapRel)
int ndeletable = 0;
OffsetNumber offnum,
maxoff;
- TransactionId latestRemovedXid = InvalidTransactionId;
Assert(GistPageIsLeaf(page));
@@ -1664,13 +1663,15 @@ gistprunepage(Relation rel, Page page, Buffer buffer, Relation heapRel)
deletable[ndeletable++] = offnum;
}
- if (XLogStandbyInfoActive() && RelationNeedsWAL(rel))
- latestRemovedXid =
- index_compute_xid_horizon_for_tuples(rel, heapRel, buffer,
- deletable, ndeletable);
-
if (ndeletable > 0)
{
+ TransactionId latestRemovedXid = InvalidTransactionId;
+
+ if (XLogStandbyInfoActive() && RelationNeedsWAL(rel))
+ latestRemovedXid =
+ index_compute_xid_horizon_for_tuples(rel, heapRel, buffer,
+ deletable, ndeletable);
+
START_CRIT_SECTION();
PageIndexMultiDelete(page, deletable, ndeletable);
diff --git a/src/backend/access/index/genam.c b/src/backend/access/index/genam.c
index c911c705ba6..1c3e937c615 100644
--- a/src/backend/access/index/genam.c
+++ b/src/backend/access/index/genam.c
@@ -301,6 +301,8 @@ index_compute_xid_horizon_for_tuples(Relation irel,
Page ipage = BufferGetPage(ibuf);
IndexTuple itup;
+ Assert(nitems > 0);
+
delstate.bottomup = false;
delstate.bottomupfreespace = 0;
delstate.ndeltids = 0;