Re: Restricting maximum keep segments by repslots

On Tue, Feb 28, 2017 at 1:16 PM, Kyotaro HORIGUCHI
<horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> It is doable without a plugin and currently we are planning to do
> in the way (Maybe such plugin would be unacceptable..). Killing
> walsender (which one?), removing the slot and if failed..

The PID and restart_lsn associated to each slot offer enough
information for monitoring.

> This is the 'steps rather complex' and fragile.

The handling of slot drop is not complex. The insurance that WAL
segments get recycled on time and avoid a full bloat is though.

>> That's as well more flexible than having a parameter
>> that basically is just a synonym of max_wal_size.
>
> I thought the same thing first, max_wal_size_hard, that limits
> the wal size including extra (other than them for the two
> checkpoig cycles) segments.

It would make more sense to just switch max_wal_size from a soft to a
hard limit. The current behavior is not cool with activity spikes.
--
Michael