Re: reloption to prevent VACUUM from truncating empty pages at theend of relation

Hi,

On 2019-03-04 22:00:47 +0000, Bossart, Nathan wrote:
> On 3/4/19, 1:44 PM, "Andres Freund" <andres@anarazel.de> wrote:
> > Yea, I do think that's a danger. But we allow disabling autovacuum, so
> > I'm not sure it matters that much... And for indexes you'd still have
> > the index page-level vacuum that'd continue to work.
> 
> I think the difference here is that there isn't something like
> autovacuum_freeze_max_age to force index cleanup at some point.
> Granted, you can set autovacuum_freeze_max_age to 2B if you want, but
> at least there's a fallback available.

Well, but your cluster doesn't suddenly shut down because of index bloat
(in contrast to xid wraparound). So I don't quite see an equivalent need
for an emergency valve.  I think we should just put a warning into the
reloption's docs, and leave it at that.

Greetings,

Andres Freund