Re: pgsql: Add support for temporary replication slots

On 2016-12-12 19:40:37 -0500, Tom Lane wrote:
> Petr Jelinek <petr(dot)jelinek(at)2ndquadrant(dot)com> writes:
> > Yes, I've seen. The cleanup of slots is done in ProcKill(), I wonder,
> > since it's on_shmem_exit hook, and the pgstat_beshutdown_hook is as
> > well, maybe the pgstat_beshutdown_hook is called before ProcKill and the
> > query is lucky to hit right in between.
>
> Hm. That seems like a pretty bogus place to do it.

Well, that'd not be Pet[e]r's fault. Robert and I had some preexisting
slot cleanpucode there (which I'd like to consolidate btw).

> backend infrastructure is already gone by then, if I recall the ordering
> correctly. Maybe ShutdownPostgres would be a saner place; but it really
> depends on what you think the module layering is for this facility.
> I would definitely not think it is proc.c's responsibility, though.

Slots quite possibly can used by bgworkers, so I don't think
ShutdownPostgres would be right. I don't think there's a perfect place
for it atm, so it's ProcKill()...

- Andres