Re: warning message in standby

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Bruce Momjian <bruce@momjian.us>, Magnus Hagander <magnus@hagander.net>, Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>, Simon Riggs <simon@2ndquadrant.com>, Fujii Masao <masao.fujii@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2010-06-14T14:57:08Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Jun 14, 2010 at 10:38 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> That's a different question altogether ;-). I assume you're not
>> satisfied by the change Heikki committed a couple hours ago?
>> It will at least try to do something to recover.

> Yeah, I'm not satisfied by that.  It's an improvement in the technical
> sense - it replaces an infinite retry that spins at top speed with a
> slower retry that won't flog your CPU quite so badly, but the chances
> that it will actually succeed in correcting the underlying problem
> seem infinitesimal.

I'm not sure about that.  walreceiver will refetch from the start of the
current WAL page, so there's at least some chance of getting a good copy
when we didn't have one before.

However, I do agree that it's not helpful to loop forever.  If we can
easily make it retry once and then PANIC, I'd be for that --- otherwise
I tend to agree that the best thing is just to PANIC immediately.  There
are many many situations where a slave resync will be necessary; a
transmission error on the WAL data is just one more.

			regards, tom lane