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To: Tomasz Chmielewski <mangoo@wpkg.org>
cc: Scott Marlowe <scott.marlowe@gmail.com>,
	Kevin Grittner <Kevin.Grittner@wicourts.gov>,
	pgsql-admin@postgresql.org, pgsql-hackers@postgresql.org
Subject: Re: 'SGT DETAIL: Could not open file "pg_clog/05DC": No such file or
	directory' - what to do now?
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Comments: In-reply-to Tomasz Chmielewski <mangoo@wpkg.org>
	message dated "Mon, 30 May 2011 11:18:17 +0200"
Date: Mon, 30 May 2011 23:16:53 -0400
Message-ID: <16063.1306811813@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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Tomasz Chmielewski <mangoo@wpkg.org> writes:
> bookstor=# SELECT 1 FROM core_wot_seq FOR UPDATE;

Um ... why are you doing that on a sequence?

> ERROR: could not access status of transaction 1573786613
> DETAIL: Could not open file "pg_clog/05DC": No such file or directory.

This doesn't surprise me too much, because sequences are not expected
to contain any live XIDs, so the XID freezing mechanism ignores them.
So if you did that in the past, this would eventually happen.

I think the most appropriate solution may be to disallow SELECT FOR
UPDATE/SHARE on sequences ... so if you have a good reason why we
shouldn't do so, please explain it.

			regards, tom lane