Date: Sat, 14 Dec 2013 14:11:59 +0100
From: Andres Freund <andres@2ndquadrant.com>
To: Simon Riggs <simon@2ndQuadrant.com>
Cc: =?iso-8859-1?Q?Fabr=EDzio?= Mello <fabriziomello@gmail.com>,
 Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>,
 KONDO Mitsumasa <kondo.mitsumasa@lab.ntt.co.jp>,
 Pavel Stehule <pavel.stehule@gmail.com>,
 Pgsql Hackers <pgsql-hackers@postgresql.org>
Subject: Re: Time-Delayed Standbys
Message-ID: <20131214131159.GA3368@awork2.anarazel.de>
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On 2013-12-13 13:44:30 +0000, Simon Riggs wrote:
> On 13 December 2013 13:22, Andres Freund <andres@2ndquadrant.com> wrote:
> > On 2013-12-13 13:09:13 +0000, Simon Riggs wrote:
> >> On 13 December 2013 11:58, Andres Freund <andres@2ndquadrant.com> wrote:
> >> >> I removed it because it was after the pause. I'll replace it, but
> >> >> before the pause.
> >> >
> >> > Doesn't after the pause make more sense? If somebody promoted while we
> >> > were waiting, we want to recognize that before rolling forward? The wait
> >> > can take a long while after all?
> >>
> >> That would change the way pause currently works, which is OOS for that patch.
> >
> > But this feature isn't pause itself - it's imo something
> > independent. Note that we currently
> > a) check pause again after recoveryApplyDelay(),
> > b) do check for promotion if the sleep in recoveryApplyDelay() is
> >    interrupted. So not checking after the final sleep seems confusing.
> 
> I'm proposing the attached patch.

LOoks good, although I'd move it down below the comment ;)

> This patch implements a consistent view of recovery pause, which is
> that when paused, we don't check for promotion, during or immediately
> after. That is user noticeable behaviour and shouldn't be changed
> without thought and discussion on a separate thread with a clear
> descriptive title. (I might argue in favour of it myself, I'm not yet
> decided).

Some more improvements in that are certainly would be good...

Greetings,

Andres Freund

-- 
 Andres Freund	                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services


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