Re: Why is lock not released?

On Sat, Aug 20, 2005 at 12:23:38AM -0400, Tom Lane wrote:
> Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> writes:
> >> The "drop" way probably allows slightly more concurrency, but given that
> >> people should seldom be taking exclusionary locks on system catalogs,
> >> I'm not sure this is really an issue.
>
> > Hmm. The problem at hand (REASSIGN OWNED BY) may involve changing
> > ownership of several objects in a single transaction. The order is
> > unspecified, because it's following a scan of the pg_shdepend entries --
> > so it'd be easy for one REASSIGN OWNED BY transaction to deadlock with
> > another one, if they happen to follow different orderings.
>
> Uh, how is it going to deadlock on a lock that is not exclusive?

Oh, so is RowExclusiveLock not exclusive? (pokes) yeah, I guess it
isn't ...

--
Alvaro Herrera (<alvherre[a]alvh.no-ip.org>)
"La grandeza es una experiencia transitoria. Nunca es consistente.
Depende en gran parte de la imaginación humana creadora de mitos"
(Irulan)