RE: Temporary tables prevent autovacuum, leading to XID wraparound

From: Michael Paquier [mailto:michael(dot)paquier(at)gmail(dot)com]
> I am not sure that we would like to give up that easily the property that
> we have now to clean up past temporary files only at postmaster startup
> and only when not in recovery. If you implement that, there is a risk that
> the backend you are starting is eating the connection slot and by consequence
> its temporary schema and its set of temporary tables on which one may want
> to look into after a crash.

postmaster deletes temporary relation files at startup by calling RemovePgTempFiles() regardless of whether it's in recovery. It doesn't call that function during auto restart after a crash when restart_after_crash is on.

> > 2. Teach autovacuum to remove any leftover tables in a pg_temp_%d
> > schema if the backend is active but in some other database (rather
> > than only when the backend is not active at all).
>
> Yeah. Here we can do something. This does not sound much difficult to
> me.

I did that in my patch.

Regards
Takayuki Tsunakawa