Re: [HACKERS] FOR SHARE vs FOR UPDATE locks

On Fri, 2006-12-01 at 02:46 -0500, Tom Lane wrote:
> Michael Paesold <mpaesold(at)gmx(dot)at> writes:
> > Now seriously, isn't this a perfectly feasible scenario? E.g. the outer
> > transaction acquires a shared lock because of foreign key constraints, and
> > the sub transaction later wants to update that row?
>
> Yeah, it's not implausible. But the only way I can see to implement
> that is to upgrade the outer xact's shared lock to exclusive, and that
> doesn't seem real cool either.
>

If it's a plausible enough sequence of events, is it worth adding a note
to the "migration" section of the release notes?

Regards,
Jeff Davis