Re: Transaction-scope advisory locks

Marko Tiikkaja <marko.tiikkaja@cs.helsinki.fi> writes:
> Another thing I now see is this:

> BEGIN;
> SELECT pg_advisory_xact_lock(1);

> -- do something here

> -- upgrade to session lock
> SELECT pg_advisory_lock(1);
> COMMIT;


> This seems useful, since the xact lock would be automatically released 
> if an error happens during "-- do something here" so you wouldn't need 
> to worry about releasing the lock elsewhere.  But I'm not sure this is 
> safe.  Can anyone see a problem with it?

I think the POLA dictates that the behavior of that should be that you
now have both a transactional and a nontransactional hold on the lock;
and only the transactional hold goes away at commit.
        regards, tom lane