Re: removal of dangling temp tables

On 2018-Dec-14, Robert Haas wrote:

> On Fri, Dec 14, 2018 at 6:35 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > Hm. It *could*, if we wanted it to run some transactions after
> > finishing recovery.
>
> It'd have to launch a separate process per database. That would be
> useful infrastructure for other things, too, like automatic catalog
> upgrades in minor releases, but I'm not volunteering to write that
> infrastructure right now.

This looks like a major project.

> > Alternatively, maybe we could have backends flag whether they've
> > taken ownership of their temp schemas or not, and let autovacuum
> > flush old temp tables if not?
>
> Yes, that seems like a possibly promising approach.

I did propose in my OP the idea of a PGPROC boolean flag that indicates
whether the temp namespace has been set up. If not, have autovac remove
those tables. I like this option better, but I fear it adds more
ProcArrayLock contention. Maybe I can just use a new LWLock to
coordinate that particular member of the ProcGlobal array ... (but then
it can no longer be a boolean.)

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Álvaro Herrera https://www.2ndQuadrant.com/
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