diff options
| author | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2024-06-27 21:06:32 +0300 |
|---|---|---|
| committer | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2024-06-27 21:08:55 +0300 |
| commit | e9c8747ee934db9b5bad0b0f5aa3709a41ad0a9c (patch) | |
| tree | e6018ceb11c55499abd80b448b30642bcde1a7b1 /src/backend/access/transam/twophase.c | |
| parent | 071e19a36c68dd5f1d949ecf9f110f1ec95a9532 (diff) | |
Fix MVCC bug with prepared xact with subxacts on standby
We did not recover the subtransaction IDs of prepared transactions
when starting a hot standby from a shutdown checkpoint. As a result,
such subtransactions were considered as aborted, rather than
in-progress. That would lead to hint bits being set incorrectly, and
the subtransactions suddenly becoming visible to old snapshots when
the prepared transaction was committed.
To fix, update pg_subtrans with prepared transactions's subxids when
starting hot standby from a shutdown checkpoint. The snapshots taken
from that state need to be marked as "suboverflowed", so that we also
check the pg_subtrans.
Backport to all supported versions.
Discussion: https://www.postgresql.org/message-id/6b852e98-2d49-4ca1-9e95-db419a2696e0@iki.fi
Diffstat (limited to 'src/backend/access/transam/twophase.c')
| -rw-r--r-- | src/backend/access/transam/twophase.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c index f8272c2f0d0..0d57fb25c27 100644 --- a/src/backend/access/transam/twophase.c +++ b/src/backend/access/transam/twophase.c @@ -1997,9 +1997,8 @@ PrescanPreparedTransactions(TransactionId **xids_p, int *nxids_p) * This is never called at the end of recovery - we use * RecoverPreparedTransactions() at that point. * - * The lack of calls to SubTransSetParent() calls here is by design; - * those calls are made by RecoverPreparedTransactions() at the end of recovery - * for those xacts that need this. + * This updates pg_subtrans, so that any subtransactions will be correctly + * seen as in-progress in snapshots taken during recovery. */ void StandbyRecoverPreparedTransactions(void) @@ -2019,7 +2018,7 @@ StandbyRecoverPreparedTransactions(void) buf = ProcessTwoPhaseBuffer(xid, gxact->prepare_start_lsn, - gxact->ondisk, false, false); + gxact->ondisk, true, false); if (buf != NULL) pfree(buf); } |