From 412ad7a55639516f284cd0ef9757d6ae5c7abd43 Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Thu, 24 Mar 2022 14:32:06 -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/xlog.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 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 4ac3871c74f..17a56152f17 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -6517,18 +6517,30 @@ CreateCheckPoint(int flags) * and we will correctly flush the update below. So we cannot miss any * xacts we need to wait for. */ - vxids = GetVirtualXIDsDelayingChkpt(&nvxids); + vxids = GetVirtualXIDsDelayingChkpt(&nvxids, DELAY_CHKPT_START); if (nvxids > 0) { do { pg_usleep(10000L); /* wait for 10 msec */ - } while (HaveVirtualXIDsDelayingChkpt(vxids, nvxids)); + } while (HaveVirtualXIDsDelayingChkpt(vxids, nvxids, + DELAY_CHKPT_START)); } pfree(vxids); CheckPointGuts(checkPoint.redo, flags); + vxids = GetVirtualXIDsDelayingChkpt(&nvxids, DELAY_CHKPT_COMPLETE); + if (nvxids > 0) + { + do + { + pg_usleep(10000L); /* wait for 10 msec */ + } while (HaveVirtualXIDsDelayingChkpt(vxids, nvxids, + DELAY_CHKPT_COMPLETE)); + } + pfree(vxids); + /* * Take a snapshot of running transactions and write this to WAL. This * allows us to reconstruct the state of running transactions during -- cgit v1.2.3