Re: table_open/table_close with different lock mode

On Fri, Jul 21, 2023 at 2:26 PM Michael Paquier <michael(at)paquier(dot)xyz> wrote:
>
> On Fri, Jul 21, 2023 at 02:05:56PM +0800, Junwang Zhao wrote:
> > I noticed there are some places calling table_open with
> > RowExclusiveLock but table_close with NoLock, like in function
> > toast_save_datum.
> >
> > Can anybody explain the underlying logic, thanks in advance.
>
> This rings a bell. This is a wanted behavior, see commit f99870d and
> its related thread:
> https://postgr.es/m/17268-d2fb426e0895abd4@postgresql.org
>

I see this patch, so all the locks held by a transaction will be released
at the commit phase, right? Can you show me where the logic is located?

> The tests added by this commit in src/test/isolation/ will show the
> difference in terms of the way the toast values get handled with and
> without the change.
> --
> Michael

--
Regards
Junwang Zhao