locks=# begin; BEGIN locks=# alter table test add column b text; ALTER TABLE locks=#
Session 2 querying pg_locks for the PID from above:
locks=# select locktype,relation::regclass,mode from pg_locks where pid = 2026 and locktype = 'relation'; locktype | relation | mode ----------+----------+--------------------- relation | test | AccessExclusiveLock relation | 17728 | AccessExclusiveLock relation | 17726 | ShareLock (3 rows)
What are these 17728 and 17726 OIDs? Nothing else is happening except these two sessions.
>>Those are probably the OIDs of the toast table and the index on it. If you commit the transaction running in Session 1 and then query >>pg_class for those OIDs, you might see more details. Of course, I am just guessing without looking into much detail.
