Re: checkpoint_timout with no WAL activity

On Mon, Nov 7, 2016 at 9:32 PM, Tom DalPozzo <t(dot)dalpozzo(at)gmail(dot)com> wrote:
> I'm using 9.5.3 . I had read about that bug but I didn't know that
> wal_level=archive is equivalent to hot_standby from this point of view! I
> guess it's equivalent in 9.5.3 too.

No, this only applies to 9.6 and onward as a result of the
introduction of wal_level = replica. archive and hot_standby are kept
as aliases for backward-compatibility.

For the rest, Amul is right. Switching a segment will happen as long
as the current segment is not empty, producing itself new WAL, and
making checkpoints happening again. Each behavior taken individually
is not harming, it's when they work together that things could be
improved. That's the combination of all those activities that the
patch I mention upthread is aiming at improving. If this gets
integrated, that won't be back-patched though as it is pretty
invasive, and that's not a bug if you think about it.
--
Michael