RE: Temporary tables prevent autovacuum, leading to XID wraparound

From: Michael Paquier [mailto:michael(dot)paquier(at)gmail(dot)com]
> On Thu, Jan 25, 2018 at 08:10:00AM +0000, Tsunakawa, Takayuki wrote:
> > I understood you suggested a new session which recycle the temp schema
> > should erase the zombie metadata of old temp tables or recreate the
> > temp schema. That sounds easy.
>
> If the new session makes use of the same temporary schema where the orphan
> table is, cleanup is possible. Now you have a problem if this is not available
> as this depends on the backend ID uniquely assigned.

Ouch, you're right. If the new session "uses the temp schema," it has a chance to clean the old temp table metadata. However, it won't help if the session doesn't try to use the temp schema by creating a temp table...

> It would be better
> to just drop the table manually at the end.

Just to solve this very incident, it's so. But this is a bug, so we need to fix it somehow.

Regards
Takayuki Tsunakawa