From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Mark Kirkwood <mark.kirkwood@catalyst.net.nz>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>
Cc: Haribabu Kommi <kommi.haribabu@gmail.com>
Cc: pgsql-hackers@postgresql.org <pgsql-hackers@postgresql.org>
Subject: Re: Per table autovacuum vacuum cost limit behaviour strange
Date: Fri, 29 Aug 2014 09:45:28 -0400
Message-ID: <20140829134528.GE7705@eldon.alvh.no-ip.org> (raw)
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Mark Kirkwood wrote:
> On 29/08/14 08:56, Alvaro Herrera wrote:
> >Robert Haas wrote:
> >
> >>I agree that you might not like that. But you might not like having
> >>the table vacuumed slower than the configured rate, either. My
> >>impression is that the time between vacuums isn't really all that
> >>negotiable for some people. I had one customer who had horrible bloat
> >>issues on a table that was vacuumed every minute; when we changed the
> >>configuration so that it was vacuumed every 15 seconds, those problems
> >>went away.
> >
> >Wow, that's extreme. For that case you can set
> >autovacuum_vacuum_cost_limit to 0, which disables the whole thing and
> >lets vacuum run at full speed -- no throttling at all. Would that
> >satisfy the concern?
>
> Well no - you might have a whole lot of big tables that you want
> vacuum to not get too aggressive on, but a few small tables that are
> highly volatile. So you want *them* vacuumed really fast to prevent
> them becoming huge tables with only a few rows therein, but your
> system might not be able to handle *all* your tables being vacuum
> full speed.
I meant setting cost limit to 0 *for those tables* only, not for all of
them.
Anyway it seems to me maybe there is room for a new table storage
parameter, say autovacuum_do_balance which means to participate in the
balancing program or not.
--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
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Cc: alvherre@2ndquadrant.com, mark.kirkwood@catalyst.net.nz, robertmhaas@gmail.com, amit.kapila16@gmail.com, kommi.haribabu@gmail.com
Subject: Re: Per table autovacuum vacuum cost limit behaviour strange
In-Reply-To: <20140829134528.GE7705@eldon.alvh.no-ip.org>
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