From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
cc: =?utf-8?B?T25kxZllaiBTdsSbdGzDrWs=?= <osvetlik@flexibee.eu>,
        pgsql-admin@postgresql.org
Subject: Re: Autovacuum of pg_database
In-reply-to: <20160506160547.GA212152@alvherre.pgsql>
References: <20160506160547.GA212152@alvherre.pgsql>
Comments: In-reply-to Alvaro Herrera <alvherre@2ndquadrant.com>
	message dated "Fri, 06 May 2016 13:05:47 -0300"
Date: Fri, 06 May 2016 12:13:47 -0400
Message-ID: <5087.1462551227@sss.pgh.pa.us>
Precedence: bulk
Sender: pgsql-admin-owner@postgresql.org

Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> Tom Lane wrote:
>> I think it's pretty obvious: autovacuum.c's rule for detecting whether
>> some other worker is already processing table X is wrong when X is a
>> shared table.  I propose the attached patch.

> Hmm, I have pretty much the same patch, except I added the flag to
> struct autovac_table and have it populated by table_recheck_autovac.
> Haven't tested this yet, which is why I hadn't posted it.

Actually, I realized after looking at it that the new wi_tableshared
field is unnecessary in my patch.  The only important part is that
knowledge of relisshared be available when we're looking for conflicting
workers, and that is entirely local in do_autovacuum().  I'd started the
patch by adding wi_tableshared, on the expectation that it would be
necessary, but it ain't ...

			regards, tom lane


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