postgresql/postgresql-wal-replay-of-locking-an-updated-tuple.patch

47 lines
1.8 KiB
Diff

commit 9a57858f1103b89a5674f0d50c5fe1f756411df6
Author: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Thu Feb 27 11:13:39 2014 -0300
Fix WAL replay of locking an updated tuple
We were resetting the tuple's HEAP_HOT_UPDATED flag as well as t_ctid on
WAL replay of a tuple-lock operation, which is incorrect when the tuple
is already updated.
Back-patch to 9.3. The clearing of both header elements was there
previously, but since no update could be present on a tuple that was
being locked, it was harmless.
Bug reported by Peter Geoghegan and Greg Stark in
CAM3SWZTMQiCi5PV5OWHb+bYkUcnCk=O67w0cSswPvV7XfUcU5g@mail.gmail.com and
CAM-w4HPTOeMT4KP0OJK+mGgzgcTOtLRTvFZyvD0O4aH-7dxo3Q@mail.gmail.com
respectively; diagnosis by Andres Freund.
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 33fc5a7..d94980b 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -7721,11 +7721,19 @@ heap_xlog_lock(XLogRecPtr lsn, XLogRecord *record)
fix_infomask_from_infobits(xlrec->infobits_set, &htup->t_infomask,
&htup->t_infomask2);
- HeapTupleHeaderClearHotUpdated(htup);
+
+ /*
+ * Clear relevant update flags, but only if the modified infomask says
+ * there's no update.
+ */
+ if (HEAP_XMAX_IS_LOCKED_ONLY(htup->t_infomask))
+ {
+ HeapTupleHeaderClearHotUpdated(htup);
+ /* Make sure there is no forward chain link in t_ctid */
+ htup->t_ctid = xlrec->target.tid;
+ }
HeapTupleHeaderSetXmax(htup, xlrec->locking_xid);
HeapTupleHeaderSetCmax(htup, FirstCommandId, false);
- /* Make sure there is no forward chain link in t_ctid */
- htup->t_ctid = xlrec->target.tid;
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);