Heikki Linnakangas wrote:
> Why does the application LOCK pg_auth?
It does it with NOWAIT to determine if some other connection had already
locked it (because it was modifying some roles) in order not to lock up
the program. This (or something like it, because this doesn't work,
after all) is unfortunately necessary because schema changes don't obey
ordinary snapshot rules.
--
Peter Eisentraut
http://developer.postgresql.org/~petere/