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| 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/storage/ipc/standby.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/storage/ipc/standby.c')
| -rw-r--r-- | src/backend/storage/ipc/standby.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c index 146b80db110..7b9bba290ac 100644 --- a/src/backend/storage/ipc/standby.c +++ b/src/backend/storage/ipc/standby.c @@ -937,7 +937,7 @@ standby_redo(XLogReaderState *record) running.xcnt = xlrec->xcnt; running.subxcnt = xlrec->subxcnt; - running.subxid_overflow = xlrec->subxid_overflow; + running.subxid_status = xlrec->subxid_overflow ? SUBXIDS_MISSING : SUBXIDS_IN_ARRAY; running.nextXid = xlrec->nextXid; running.latestCompletedXid = xlrec->latestCompletedXid; running.oldestRunningXid = xlrec->oldestRunningXid; @@ -1093,7 +1093,7 @@ LogCurrentRunningXacts(RunningTransactions CurrRunningXacts) xlrec.xcnt = CurrRunningXacts->xcnt; xlrec.subxcnt = CurrRunningXacts->subxcnt; - xlrec.subxid_overflow = CurrRunningXacts->subxid_overflow; + xlrec.subxid_overflow = (CurrRunningXacts->subxid_status != SUBXIDS_IN_ARRAY); xlrec.nextXid = CurrRunningXacts->nextXid; xlrec.oldestRunningXid = CurrRunningXacts->oldestRunningXid; xlrec.latestCompletedXid = CurrRunningXacts->latestCompletedXid; @@ -1110,7 +1110,7 @@ LogCurrentRunningXacts(RunningTransactions CurrRunningXacts) recptr = XLogInsert(RM_STANDBY_ID, XLOG_RUNNING_XACTS); - if (CurrRunningXacts->subxid_overflow) + if (xlrec.subxid_overflow) elog(trace_recovery(DEBUG2), "snapshot of %u running transactions overflowed (lsn %X/%X oldest xid %u latest complete %u next xid %u)", CurrRunningXacts->xcnt, |