From 6264cd3d69b519b6e6f2470e3c23ad1ef1ddff66 Mon Sep 17 00:00:00 2001
From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Wed, 12 Dec 2012 13:34:03 +0200
Subject: [PATCH] In multi-insert, don't go into infinite loop on a huge tuple
and fillfactor.
If a tuple is larger than page size minus space reserved for fillfactor,
heap_multi_insert would never find a page that it fits in and repeatedly ask
for a new page from RelationGetBufferForTuple. If a tuple is too large to
fit on any page, taking fillfactor into account, RelationGetBufferForTuple
will always expand the relation. In a normal insert, heap_insert will accept
that and put the tuple on the new page. heap_multi_insert, however, does a
fillfactor check of its own, and doesn't accept the newly-extended page
RelationGetBufferForTuple returns, even though there is no other choice to
make the tuple fit.
Fix that by making the logic in heap_multi_insert more like the heap_insert
logic. The first tuple is always put on the page RelationGetBufferForTuple
gives us, and the fillfactor check is only applied to the subsequent tuples.
Report from David Gould, although I didn't use his patch.
---
src/backend/access/heap/heapam.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 74c41fac3e9..e114d3dc45b 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -2185,8 +2185,12 @@ heap_multi_insert(Relation relation, HeapTuple *tuples, int ntuples,
/* NO EREPORT(ERROR) from here till changes are logged */
START_CRIT_SECTION();
- /* Put as many tuples as fit on this page */
- for (nthispage = 0; ndone + nthispage < ntuples; nthispage++)
+ /*
+ * RelationGetBufferForTuple has ensured that the first tuple fits.
+ * Put that on the page, and then as many other tuples as fit.
+ */
+ RelationPutHeapTuple(relation, buffer, heaptuples[ndone]);
+ for (nthispage = 1; ndone + nthispage < ntuples; nthispage++)
{
HeapTuple heaptup = heaptuples[ndone + nthispage];
--
GitLab