From 86e33648992cfc104836ab1fbb6e654308beb4a5 Mon Sep 17 00:00:00 2001 From: Simon Riggs Date: Wed, 2 Nov 2011 08:54:56 +0000 Subject: Derive oldestActiveXid at correct time for Hot Standby. There was a timing window between when oldestActiveXid was derived and when it should have been derived that only shows itself under heavy load. Move code around to ensure correct timing of derivation. No change to StartupSUBTRANS() code, which is where this failed. Bug report by Chris Redekop --- src/backend/access/transam/xlog.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'src/backend/access/transam/xlog.c') diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index bf57b3bf49e..0944aa4162d 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -7636,6 +7636,16 @@ CreateCheckPoint(int flags) MemSet(&checkPoint, 0, sizeof(checkPoint)); checkPoint.time = (pg_time_t) time(NULL); + /* + * For Hot Standby, derive the oldestActiveXid before we fix the redo pointer. + * This allows us to begin accumulating changes to assemble our starting + * snapshot of locks and transactions. + */ + if (!shutdown && XLogStandbyInfoActive()) + checkPoint.oldestActiveXid = GetOldestActiveTransactionId(); + else + checkPoint.oldestActiveXid = InvalidTransactionId; + /* * We must hold WALInsertLock while examining insert state to determine * the checkpoint REDO pointer. @@ -7822,9 +7832,7 @@ CreateCheckPoint(int flags) * Update checkPoint.nextXid since we have a later value */ if (!shutdown && XLogStandbyInfoActive()) - LogStandbySnapshot(&checkPoint.oldestActiveXid, &checkPoint.nextXid); - else - checkPoint.oldestActiveXid = InvalidTransactionId; + LogStandbySnapshot(&checkPoint.nextXid); START_CRIT_SECTION(); -- cgit v1.2.3