Received: from malur.postgresql.org ([217.196.149.56])
 by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from
 <pgsql-general-owner+M201687=pgsql-general-arkari@postgresql.org>)
 id 1VgkFS-0007Z0-HH
 for pgsql-general@arkaria.postgresql.org; Wed, 13 Nov 2013 23:53:26 +0000
Received: from localhost ([127.0.0.1] helo=postgresql.org)
 by malur.postgresql.org with smtp (Exim 4.80) (envelope-from
 <pgsql-general-owner+M201687=pgsql-general-arkari@postgresql.org>)
 id 1VgkFS-0007dN-0r
 for pgsql-general@arkaria.postgresql.org; Wed, 13 Nov 2013 23:53:26 +0000
Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29])
 by malur.postgresql.org with esmtp (Exim 4.80)
 (envelope-from <eshkinkot@gmail.com>) id 1VgkFR-0007dF-1v
 for pgsql-general@postgresql.org; Wed, 13 Nov 2013 23:53:25 +0000
Received: from mail-la0-x22a.google.com ([2a00:1450:4010:c03::22a])
 by magus.postgresql.org with esmtp (Exim 4.80)
 (envelope-from <eshkinkot@gmail.com>) id 1VgkFO-0006Yb-Iy
 for pgsql-general@postgresql.org; Wed, 13 Nov 2013 23:53:24 +0000
Received: by mail-la0-f42.google.com with SMTP id ec20so986388lab.29
 for <pgsql-general@postgresql.org>; Wed, 13 Nov 2013 15:53:21 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113;
 h=from:to:cc:subject:references:date:in-reply-to:message-id
 :user-agent:mime-version:content-type;
 bh=Adl/HMCNRrd6OcVy6dlj41WZYhbkEW31iROZa7Q0Zus=;
 b=hgvqq5oge20CzrZ73nO8Bim+6nYM0O5CSDRrBWqRe91A5YXlUyjpWgb+U0jsU9ZGkz
 rGxsSxAwbgOspqeM1zcAVry4LdNdxU/C7LNcVJhx2RBF74agfm+P5c6bAoksxpLrb9mx
 L1ynHuJxm2B6LeuSgT1N9M6PSoQwZNrJj4wjsbUSd7jd0jqaIbWrEs1QJZ8sIKLKOK40
 FMIQgOYnB3lZ63PNgN3zX3W++7lusQyeGizvCH9hX4ryzAzF9jFG2ESr+CKhsI1uKROc
 Yt0MXdf8Fbj8hvBK7MOhbd+0a8+nKXTACHG1uMbMHOka9tLQyXoDEayQG8n5PxTYy59b
 H0iQ==
X-Received: by 10.112.51.101 with SMTP id j5mr31704651lbo.17.1384386800982;
 Wed, 13 Nov 2013 15:53:20 -0800 (PST)
Received: from home.progtech.ru (os.progtech.ru. [80.252.153.41])
 by mx.google.com with ESMTPSA id pg3sm24670042lbb.7.2013.11.13.15.53.19
 for <multiple recipients>
 (version=TLSv1.2 cipher=RC4-SHA bits=128/128);
 Wed, 13 Nov 2013 15:53:19 -0800 (PST)
From: Sergey Burladyan <eshkinkot@gmail.com>
To: Jeff Janes <jeff.janes@gmail.com>
Cc: =?utf-8?B?0JzQuNGI0LAg0KLRjtGA0LjQvQ==?= <tmihail@bk.ru>, Tom Lane
 <tgl@sss.pgh.pa.us>, pgsql-general <pgsql-general@postgresql.org>
Subject: Re: freeze cannot be finished
References: <1384356585.995240612@f50.i.mail.ru>
 <CAMkU=1wQ1wWc=MTEm9=Z23NOCAzu6aLOKhQj2oQY5AcFuTeq3g@mail.gmail.com>
Date: Thu, 14 Nov 2013 03:53:17 +0400
In-Reply-To: 
 <CAMkU=1wQ1wWc=MTEm9=Z23NOCAzu6aLOKhQj2oQY5AcFuTeq3g@mail.gmail.com>
 (Jeff Janes's message of "Wed, 13 Nov 2013 12:37:01 -0800")
Message-ID: <87txffkgeq.fsf@home.progtech.ru>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux)
MIME-Version: 1.0
Content-Type: text/plain
X-Pg-Spam-Score: -2.0 (--)
List-Archive: <http://archives.postgresql.org/pgsql-general>
List-Help: <mailto:majordomo@postgresql.org?body=help>
List-ID: <pgsql-general.postgresql.org>
List-Owner: <mailto:pgsql-general-owner@postgresql.org>
List-Post: <mailto:pgsql-general@postgresql.org>
List-Subscribe: <mailto:majordomo@postgresql.org?body=sub%20pgsql-general>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-general>
X-Mailing-List: pgsql-general
Precedence: bulk
Sender: pgsql-general-owner@postgresql.org

Jeff Janes <jeff.janes@gmail.com> writes:

If I not mistaken, looks like lazy_scan_heap() called from lazy_vacuum_rel()
(see [1]) skip pages, even if it run with scan_all == true, lazy_scan_heap()
does not increment scanned_pages if lazy_check_needs_freeze() return false, so
if this occurred at wraparound vacuum it cannot update pg_class, because
pg_class updated via this code:

    new_frozen_xid = FreezeLimit;
    if (vacrelstats->scanned_pages < vacrelstats->rel_pages)
        new_frozen_xid = InvalidTransactionId;

    vac_update_relstats(onerel,
                        new_rel_pages,
                        new_rel_tuples,
                        new_rel_allvisible,
                        vacrelstats->hasindex,
                        new_frozen_xid);

so i think in our prevent wraparound vacuum vacrelstats->scanned_pages always
less than vacrelstats->rel_pages and pg_class relfrozenxid never updated.

[1] src/backend/commands/vacuumlazy.c

-- 
Sergey Burladyan


-- 
Sent via pgsql-general mailing list (pgsql-general@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general