Re: BUG #17103: WAL segments are not removed after exceeding max_slot_wal_keep_size

On Thu, Jul 15, 2021 at 1:22 AM Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com>
wrote:

> At Wed, 14 Jul 2021 19:10:26 -0400, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
> wrote in
> > On Tue, Jul 13, 2021 at 10:12 PM Kyotaro Horiguchi <
> horikyota(dot)ntt(at)gmail(dot)com>
> > wrote:
> > > Useless WAL files will be removd after a checkpoint runs.
> > >
> >
> > They should be, but they are not. That is the bug. They just hang
> > around, checkpoint after checkpoint. Some of them do get cleaned up, to
> > make up for new ones created during that cycle. It treats
> > max_slot_wal_keep the same way it treats wal_keep_size (but only if a
> > "lost" slot is hanging around). If you drop the lost slot, only then
> does
> > it remove all the accumulated WAL at the next checkpoint.
>
> Thanks! I saw the issue here. Some investigation showd me a doubious
> motion of XLogCtl->repliationSlotMinLSN. Slot invalidation is
> forgetting to recalculate it and that misbehavior retreats the segment
> horizon.
>
> So the attached worked for me. I'll repost the polished version
> including test.
>

Thank you. That works for me. But I did not test on Windows.

* Some slots may have been gone,

"been invalidated" reads better than "been gone", and matches the wording
used elsewhere.

Cheers,

Jeff