Re: Log messages regarding automatic vacuum and exclusive locks

From: Sergey Konoplev <gray(dot)ru(at)gmail(dot)com>
To: jonesd(at)xmission(dot)com
Cc: pgsql-general <pgsql-general(at)postgresql(dot)org>
Subject: Re: Log messages regarding automatic vacuum and exclusive locks
Date: 2013-04-24 03:08:05
Message-ID: CAL_0b1uk7DXb9QXvc+tGx4hk8Fz3cNPkcYfCxHDe2LxubC1QCw@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general

On Tue, Apr 23, 2013 at 8:50 AM, <jonesd(at)xmission(dot)com> wrote:
> Good morning. I'm seeing several of the following log messages each morning
> (for example, there were five this morning, spaced approximately one minute
> apart, with the closest interval between messages being 44 seconds).
> They're occurring during a daily cycle of deleting all rows from a table and
> then repopulating it from another database; the first message came

If all the rows are deleted from the table every time to repopulate it
later, I would suggest using TRUNCATE table_name; instead DELETE FROM
table_name. TRUNCATE does not left any free space in the table so
autovacuum will have nothing to do with it.

> LOG: automatic vacuum of table "x.y.z": could not (re)acquire exclusive
> lock for truncate scan

Hence you will not get this messages and BTW it will be faster.

>
> I'm using default settings for autovacuum, with server version 9.2.4.
>
> Some other smaller tables produce the same messages during the same process,
> but apparently less frequently.
>
> Any thoughts on the cause? Chapters 18 and 23 of the documentation provided
> some hints, but nothing conclusive.
>
>
> Thanks in advance,
>
> Dominic Jones
>
>
> --
> Sent via pgsql-general mailing list (pgsql-general(at)postgresql(dot)org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-general

--
Kind regards,
Sergey Konoplev
Database and Software Consultant

Profile: http://www.linkedin.com/in/grayhemp
Phone: USA +1 (415) 867-9984, Russia +7 (901) 903-0499, +7 (988) 888-1979
Skype: gray-hemp
Jabber: gray(dot)ru(at)gmail(dot)com

In response to

Responses

Browse pgsql-general by date

  From Date Subject
Next Message Sergey Konoplev 2013-04-24 03:23:32 Re: run COPY as user other than postgres
Previous Message John R Pierce 2013-04-24 02:59:53 Re: Regarding template1 database