From 294509ea9bb3305230659fd76bd355aec6fcd039 Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Wed, 25 May 2016 19:39:49 -0400
Subject: [PATCH] Avoid hot standby cancels from VAC FREEZE
VACUUM FREEZE generated false cancelations of standby queries on an
otherwise idle master. Caused by an off-by-one error on cutoff_xid
which goes back to original commit.
Analysis and report by Marco Nenciarini
Bug fix by Simon Riggs
This is a correct backpatch of commit 66fbcb0d2e to branches 9.1 through
9.4. That commit was backpatched to 9.0 originally, but it was
immediately reverted in 9.0-9.4 because it didn't compile.
---
src/backend/access/heap/heapam.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index eb8eada27d6..434880ac295 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -4764,7 +4764,13 @@ heap_xlog_freeze(XLogRecPtr lsn, XLogRecord *record)
* consider the frozen xids as running.
*/
if (InHotStandby)
- ResolveRecoveryConflictWithSnapshot(cutoff_xid, xlrec->node);
+ {
+ TransactionId latestRemovedXid = cutoff_xid;
+
+ TransactionIdRetreat(latestRemovedXid);
+
+ ResolveRecoveryConflictWithSnapshot(latestRemovedXid, xlrec->node);
+ }
/* If we have a full-page image, restore it and we're done */
if (record->xl_info & XLR_BKP_BLOCK(0))
--
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