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 23:42:57 +0200 |
| commit | acd5c28db5d0cdb9446c5cb09996629f78287b82 (patch) | |
| tree | 6d050188bf92dc18fa07c75cdc8428f795a61fd2 /src/backend/utils/time/snapmgr.c | |
| parent | fb540b6aa5abe68d7ba1d84a90f5afd9c78564e3 (diff) | |
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 5bc2a15160d..2c8ecdb7ef3 100644 --- a/src/backend/utils/time/snapmgr.c +++ b/src/backend/utils/time/snapmgr.c @@ -948,7 +948,7 @@ SnapshotResetXmin(void) if (pairingheap_is_empty(&RegisteredSnapshots)) { - MyProc->xmin = InvalidTransactionId; + MyProc->xmin = TransactionXmin = InvalidTransactionId; return; } @@ -956,7 +956,7 @@ SnapshotResetXmin(void) pairingheap_first(&RegisteredSnapshots)); if (TransactionIdPrecedes(MyProc->xmin, minSnapshot->xmin)) - MyProc->xmin = minSnapshot->xmin; + MyProc->xmin = TransactionXmin = minSnapshot->xmin; } /* |