Date: Mon, 12 Dec 2016 17:11:01 -0800
From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Petr Jelinek <petr.jelinek@2ndquadrant.com>,
	Peter Eisentraut <peter_e@gmx.net>, pgsql-committers@postgresql.org
Subject: Re: pgsql: Add support for temporary replication slots
Message-ID: <20161213011101.xctlra2ujq6zpnzm@alap3.anarazel.de>
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On 2016-12-12 20:08:01 -0500, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > On 2016-12-13 01:57:01 +0100, Petr Jelinek wrote:
> >> I mentioned that as possible solution upthread, I am only worried that
> >> the failure scenario is basically infinite loop.
> 
> > I don't see the problem with that. If you're really concerned you can
> > set a statement timeout.
> 
> I don't think "change the test" is the right response here.
> I think the problem is that we're disconnecting from the slot at the
> wrong step of backend shutdown, and that we need to fix that before
> it bites us on some more painful parts of our anatomies.  You can't
> just throw darts at the code when deciding where to do things, and
> proc.c is NOT the place that should be concerned with replication
> slots.

And why is that / where would be more appropriate? It's not
ShutdownPostgres() (usable from bgworkers). And it has to be
after LWLockReleaseAll(), because otherwise we'll potentially just
deadlock against ourselves.

Greetings,

Andres Freund


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