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Date: Mon, 15 Feb 2010 15:29:57 +0900
Message-ID: <3f0b79eb1002142229k639aad8dk7233175c5484ef6d@mail.gmail.com>
Subject: Re: Re: [COMMITTERS] pgsql: Make standby server
	continuously retry restoring the next WAL
From: Fujii Masao <masao.fujii@gmail.com>
To: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Cc: Simon Riggs <simon@2ndquadrant.com>,
	Dimitri Fontaine <dfontaine@hi-media.com>,
	PostgreSQL-development <pgsql-hackers@postgresql.org>
Content-Type: text/plain; charset=ISO-8859-1

On Sat, Feb 13, 2010 at 1:10 AM, Heikki Linnakangas
<heikki.linnakangas@enterprisedb.com> wrote:
> Are you thinking of a scenario where remove_command gets stuck, and
> prevents bgwriter from performing restartpoints while it's stuck?

Yes. If there is the archive in the remote server and the network outage
happens, remove_command might get stuck, I'm afraid.

> You
> have trouble if restore_command gets stuck like that as well, so I think
> we can require that the remove_command returns in a reasonable period of
> time, ie. in a few minutes.

Oh, you are right!

BTW, we need to note that remove_command approach would be useless if one
archive is shared by multiple standbys. One standby might wrongly remove
the archived WAL file that has been still required for another standby.
In this case, we need to have the job script that calculates the archived
WAL files that are required by no standbys, and removes them.

Regards,

-- 
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center