Re: Race conditions with WAL sender PID lookups

On 2017-05-20 14:40, Michael Paquier wrote:
> On Fri, May 19, 2017 at 3:01 PM, Masahiko Sawada
> <sawada(dot)mshk(at)gmail(dot)com> wrote:
>> Also, as Horiguchi-san pointed out earlier, walreceiver seems need the
>> similar fix.
>
> Actually, now that I look at it, ready_to_display should as well be
> protected by the lock of the WAL receiver, so it is incorrectly placed
> in walreceiver.h. As you are pointing out, pg_stat_get_wal_receiver()
> is lazy as well, and that's new in 10, so we have an open item here
> for both of them. And I am the author for both things. No issues
> spotted in walreceiverfuncs.c after review.
>
> I am adding an open item so as both issues are fixed in PG10. With the
> WAL sender part, I think that this should be a group shot.
>
> So what do you think about the attached?

> [walsnd-pid-races-v3.patch]

With this patch on current master my logical replication tests
(pgbench-over-logical-replication) run without errors for the first time
in many days (even weeks).

I'll do still more and longer tests but I have gathered already a long
streak of successful runs since you posted the patch so I am getting
convinced this patch is solved the problem that I was experiencing.

Pity it didn't make the beta.

thanks,

Erik Rijkers