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Fix possible recovery trouble if TRUNCATE overlaps a checkpoint.

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
This commit is contained in:
Robert Haas
2022-03-24 14:32:06 -04:00
parent 86459b3296
commit 412ad7a556
11 changed files with 120 additions and 28 deletions

View File

@ -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