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| author | Noah Misch <noah@leadboat.com> | 2024-06-27 19:21:05 -0700 |
|---|---|---|
| committer | Noah Misch <noah@leadboat.com> | 2024-06-27 19:21:10 -0700 |
| commit | fc8c25806e84c38f3920fd3507a389eac34d62a5 (patch) | |
| tree | 8c66d532dff9142d5766a93a1dc93993eada0b40 | |
| parent | 480b58fabd353015319f6621ff8c351bf3a6d520 (diff) | |
| download | postgresql-fc8c25806e84c38f3920fd3507a389eac34d62a5.tar.gz postgresql-fc8c25806e84c38f3920fd3507a389eac34d62a5.zip | |
AccessExclusiveLock new relations just after assigning the OID.
This has no user-visible, important consequences, since other sessions'
catalog scans can't find the relation until we commit. However, this
unblocks introducing a rule about locks required to heap_update() a
pg_class row. CREATE TABLE has been acquiring this lock eventually, but
it can heap_update() pg_class.relchecks earlier. create_toast_table()
has been acquiring only ShareLock. Back-patch to v12 (all supported
versions), the plan for the commit relying on the new rule.
Reviewed (in an earlier version) by Robert Haas.
Discussion: https://postgr.es/m/20240611024525.9f.nmisch@google.com
| -rw-r--r-- | src/backend/catalog/heap.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c index 531616ef462..50c9a18d101 100644 --- a/src/backend/catalog/heap.c +++ b/src/backend/catalog/heap.c @@ -1240,6 +1240,13 @@ heap_create_with_catalog(const char *relname, } /* + * Other sessions' catalog scans can't find this until we commit. Hence, + * it doesn't hurt to hold AccessExclusiveLock. Do it here so callers + * can't accidentally vary in their lock mode or acquisition timing. + */ + LockRelationOid(relid, AccessExclusiveLock); + + /* * Determine the relation's initial permissions. */ if (use_user_acl) |