Stephan Szabo wrote:
>
> On Tue, 18 Dec 2001, Tom Lane wrote:
>
> > The ri_triggers code has a lot of places that open things NoLock,
> > but it only looks into the relcache entry and doesn't try to scan
> > the relation. Nonetheless that code bothers me; we could be using
> > an obsolete relcache entry if someone has just committed an ALTER
> > TABLE on the relation. Some of the cases may be safe because a lock
> > is held higher up (eg, on the table from which the trigger was fired)
> > but I doubt they all are.
>
> Probably not, since it looks like that's being done for the other table of
> the constraint (not the one on which the trigger was fired).
If a lock is held already, acquiring an AccessShareLock
would cause no addtional conflict. I don't see any reason
to walk a tightrope with NoLock intentionally.
regards,
Hiroshi Inoue
