From bbace5697df12398e87ffd9879171c39d27f5b33 Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Thu, 24 Mar 2022 14:32:24 -0400 Subject: Fix possible recovery trouble if TRUNCATE overlaps a checkpoint. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If TRUNCATE causes some buffers to be invalidated and thus the checkpoint does not flush them, TRUNCATE must also ensure that the corresponding files are truncated on disk. Otherwise, a replay from the checkpoint might find that the buffers exist but have the wrong contents, which may cause replay to fail. Report by Teja Mupparti. Patch by Kyotaro Horiguchi, per a design suggestion from Heikki Linnakangas, with some changes to the comments by me. Review of this and a prior patch that approached the issue differently by Heikki Linnakangas, Andres Freund, Álvaro Herrera, Masahiko Sawada, and Tom Lane. Discussion: http://postgr.es/m/BYAPR06MB6373BF50B469CA393C614257ABF00@BYAPR06MB6373.namprd06.prod.outlook.com --- src/backend/access/transam/multixact.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'src/backend/access/transam/multixact.c') diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c index b643564f16a..50d8bab9e21 100644 --- a/src/backend/access/transam/multixact.c +++ b/src/backend/access/transam/multixact.c @@ -3075,8 +3075,8 @@ TruncateMultiXact(MultiXactId newOldestMulti, Oid newOldestMultiDB) * crash/basebackup, even though the state of the data directory would * require it. */ - Assert(!MyProc->delayChkpt); - MyProc->delayChkpt = true; + Assert((MyProc->delayChkpt & DELAY_CHKPT_START) == 0); + MyProc->delayChkpt |= DELAY_CHKPT_START; /* WAL log truncation */ WriteMTruncateXlogRec(newOldestMultiDB, @@ -3102,7 +3102,7 @@ TruncateMultiXact(MultiXactId newOldestMulti, Oid newOldestMultiDB) /* Then offsets */ PerformOffsetsTruncation(oldestMulti, newOldestMulti); - MyProc->delayChkpt = false; + MyProc->delayChkpt &= ~DELAY_CHKPT_START; END_CRIT_SECTION(); LWLockRelease(MultiXactTruncationLock); -- cgit v1.2.3