diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/utils/time/snapmgr.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/src/backend/utils/time/snapmgr.c b/src/backend/utils/time/snapmgr.c index 4bddaed33ba..1ec9f70f0ee 100644 --- a/src/backend/utils/time/snapmgr.c +++ b/src/backend/utils/time/snapmgr.c @@ -399,14 +399,14 @@ GetLatestSnapshot(void) /* * GetOldestSnapshot * - * Get the oldest known snapshot, as judged by the LSN. + * Get the transaction's oldest known snapshot, as judged by the LSN. + * Will return NULL if there are no active or registered snapshots. */ Snapshot GetOldestSnapshot(void) { Snapshot OldestRegisteredSnapshot = NULL; XLogRecPtr RegisteredLSN = InvalidXLogRecPtr; - XLogRecPtr ActiveLSN = InvalidXLogRecPtr; if (!pairingheap_is_empty(&RegisteredSnapshots)) { @@ -416,10 +416,12 @@ GetOldestSnapshot(void) } if (OldestActiveSnapshot != NULL) - ActiveLSN = OldestActiveSnapshot->as_snap->lsn; + { + XLogRecPtr ActiveLSN = OldestActiveSnapshot->as_snap->lsn; - if (XLogRecPtrIsInvalid(RegisteredLSN) || RegisteredLSN > ActiveLSN) - return OldestActiveSnapshot->as_snap; + if (XLogRecPtrIsInvalid(RegisteredLSN) || RegisteredLSN > ActiveLSN) + return OldestActiveSnapshot->as_snap; + } return OldestRegisteredSnapshot; } |