diff options
| author | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2024-12-21 23:42:39 +0200 |
|---|---|---|
| committer | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2024-12-21 23:42:39 +0200 |
| commit | 578a7fe7b6f8484f6d7caa2fda288abb3fe87aa0 (patch) | |
| tree | 02d74e1bf71a790b3657d8d389ab0876012a44c6 /src/backend/utils/time/snapmgr.c | |
| parent | db448ce5ad36a2754e4e75900b180260143aacf8 (diff) | |
| download | postgresql-578a7fe7b6f8484f6d7caa2fda288abb3fe87aa0.tar.gz postgresql-578a7fe7b6f8484f6d7caa2fda288abb3fe87aa0.zip | |
Update TransactionXmin when MyProc->xmin is updated
GetSnapshotData() set TransactionXmin = MyProc->xmin, but when
SnapshotResetXmin() advanced MyProc->xmin, it did not advance
TransactionXmin correspondingly. That meant that TransactionXmin could
be older than MyProc->xmin, and XIDs between than TransactionXmin and
the real MyProc->xmin could be vacuumed away. One known consequence is
in pg_subtrans lookups: we might try to look up the status of an XID
that was already truncated away.
Back-patch to all supported versions.
Reviewed-by: Andres Freund
Discussion: https://www.postgresql.org/message-id/d27a046d-a1e4-47d1-a95c-fbabe41debb4@iki.fi
Diffstat (limited to 'src/backend/utils/time/snapmgr.c')
| -rw-r--r-- | src/backend/utils/time/snapmgr.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/backend/utils/time/snapmgr.c b/src/backend/utils/time/snapmgr.c index e60360338d5..e002d0c1368 100644 --- a/src/backend/utils/time/snapmgr.c +++ b/src/backend/utils/time/snapmgr.c @@ -875,7 +875,7 @@ SnapshotResetXmin(void) if (pairingheap_is_empty(&RegisteredSnapshots)) { - MyProc->xmin = InvalidTransactionId; + MyProc->xmin = TransactionXmin = InvalidTransactionId; return; } @@ -883,7 +883,7 @@ SnapshotResetXmin(void) pairingheap_first(&RegisteredSnapshots)); if (TransactionIdPrecedes(MyProc->xmin, minSnapshot->xmin)) - MyProc->xmin = minSnapshot->xmin; + MyProc->xmin = TransactionXmin = minSnapshot->xmin; } /* |