From 6537a48c5521cb2fc401e18fe678633a688965b5 Mon Sep 17 00:00:00 2001 From: Alvaro Herrera 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 | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index 78746d15b95..1f1bac5c6be 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -6928,7 +6928,13 @@ 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)) @@ -7103,7 +7109,13 @@ heap_xlog_freeze_page(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))