From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
cc: Jeff Janes <jeff.janes@gmail.com>,
        Michael Paquier <michael.paquier@gmail.com>,
        PostgreSQL mailing lists <pgsql-hackers@postgresql.org>
Subject: Re: Reducing pg_ctl's reaction time
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Comments: In-reply-to Tom Lane <tgl@sss.pgh.pa.us>
	message dated "Mon, 26 Jun 2017 16:26:00 -0400"
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Date: Mon, 26 Jun 2017 16:39:50 -0400
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I wrote:
> Andres Freund <andres@anarazel.de> writes:
>> It'd not be unreasonble to check pg_control first, and only after that
>> indicates readyness check via the protocol.

> Hm, that's a thought.  The problem here isn't the frequency of checks,
> but the log spam.

Actually, that wouldn't help much as things stand, because you can't
tell from pg_control whether hot standby is active.  Assuming that
we want "pg_ctl start" to come back as soon as connections are allowed,
it'd have to start probing when it sees DB_IN_ARCHIVE_RECOVERY, which
means Jeff still has a problem with long recovery sessions.

We could maybe address that by changing the set of states in pg_control
(or perhaps simpler, adding a "hot standby active" flag there).  That
might have wider consequences than we really want to deal with post-beta1
though.

			regards, tom lane


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