Date: Tue, 30 Sep 2014 19:16:44 -0300
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Mark Kirkwood <mark.kirkwood@catalyst.net.nz>,
 Amit Kapila <amit.kapila16@gmail.com>,
 Haribabu Kommi <kommi.haribabu@gmail.com>,
 "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: Per table autovacuum vacuum cost limit behaviour
 strange
Message-ID: <20140930221644.GR5311@eldon.alvh.no-ip.org>
References: 
 <CAJrrPGcpZ5g5snz0PO4EEKFkTAD=uJi0VF6ruW25Mh0F34rPDw@mail.gmail.com>
 <CAJrrPGdK=nhTHUCsURgXQyG6RH=rJ8b4CdYhzGhwH=UuzaO9Ng@mail.gmail.com>
 <CAA4eK1JALkZOLnGdpqQgKbb+vq0eri1b7ytDfZLA8E9ZM35NHw@mail.gmail.com>
 <CAJrrPGeEwsezwA6+DpA2Y7MBJmEnNWwD5Gi4Ve_EqCxHoyHj3Q@mail.gmail.com>
 <CAA4eK1LwFs9iM-rUdfOrZE5MvjSxMM9ZbPbzv1SeWgGYu-O=VQ@mail.gmail.com>
 <53672F63.3080400@catalyst.net.nz>
 <CAA4eK1KDAUP=g59ku_0ekDoRjaGfEamyadQn5rJVt3j5oErLXg@mail.gmail.com>
 <53686F22.8030300@catalyst.net.nz>
 <20140826161911.GE6343@eldon.alvh.no-ip.org>
 <CA+Tgmoav37msTP0pVsrEYz4LBYU6SETMZGYTgPo5AEOC0yCMbA@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: 
 <CA+Tgmoav37msTP0pVsrEYz4LBYU6SETMZGYTgPo5AEOC0yCMbA@mail.gmail.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org

Robert Haas wrote:

> I favor option (a).   There's something to be said for your proposal
> in terms of logical consistency with what we have now, but to be
> honest I'm not sure it's the behavior anyone wants (I would welcome
> more feedback on what people actually want).  I think we should view
> an attempt to set a limit for a particular table as a way to control
> the rate at which that table is vacuumed - period.

After re-reading this whole thread one more time, I think I have come to
agree with you and Amit here, because not only it is simpler to
implement, but it is also simpler to document.  Per Greg Smith's opinion
elsewhere in the thread, it seems that for end users it doesn't make
sense to make the already complicated mechanism even more complicated.

So in essence what we're going to do is that the balance mechanism
considers only tables that don't have per-table configuration options;
for those that do, we will use the values configured there without any
changes.

I'll see about implementing this and making sure it finds its way to
9.4beta3.

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services


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