Re: Clean shutdown and warm standby

From: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
To: Simon Riggs <simon(at)2ndQuadrant(dot)com>
Cc: Guillaume Smet <guillaume(dot)smet(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Andreas Pflug <pgadmin(at)pse-consulting(dot)de>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Clean shutdown and warm standby
Date: 2009-05-28 15:02:13
Message-ID: 4A1EA775.3090705@enterprisedb.com
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Simon Riggs wrote:
> On Thu, 2009-05-28 at 17:21 +0300, Heikki Linnakangas wrote:
>> Simon Riggs wrote:
>>> I don't think it does, please look again.
>> Still looks ok to me. pgarch_ArchiverCopyLoop() loops until all ready
>> WAL segments have been archived (assuming no errors).
>
> No, it doesn't now, though it did used to. line 440.

postmaster never sends SIGTERM to pgarch, and postmaster is still alive.

>>>> Ok, we're good then I guess.
>>> No, because as I said, if archive_command has been returning non-zero
>>> then the archive will be incomplete.
>> Yes. You think that's wrong? How would you like it to behave, then? I
>> don't think you want the shutdown to wait indefinitely until all files
>> have been archived if there's an error.
>
> The complaint was that we needed to run a manual step to synchronise the
> pg_xlog directory on the standby. We still need to do that, even after
> the patch has been committed because 2 cases are not covered, so what is
> the point of the recent change? It isn't enough. It *might* be enough,
> most of the time, but you have no way of knowing that is the case and it
> is dangerous not to check.

So you check. This solves Guillaume's immediate concern. If you have a
suggestion for further improvements, I'm all ears.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com

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