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Re: autovacuum not prioritising for-wraparound tables

From: Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Christopher Browne <cbbrowne(at)gmail(dot)com>,Andres Freund <andres(at)2ndquadrant(dot)com>,Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>,Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>,Pg Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: autovacuum not prioritising for-wraparound tables
Date: 2013-01-31 20:18:24
Message-ID: 20130131201824.GF4883@alvh.no-ip.org (view raw or flat)
Thread:
Lists: pgsql-hackers
Robert Haas escribió:
> On Thu, Jan 31, 2013 at 2:40 PM, Alvaro Herrera
> <alvherre(at)2ndquadrant(dot)com> wrote:
> > Alvaro Herrera escribió:
> >
> >> Okay, here's a patch along these lines.  I haven't considered Jim's
> >> suggestion downthread about discounting dead tuples from relpages; maybe
> >> we can do that by subtracting the pages attributed to dead ones,
> >> estimating via tuple density (reltuples/relpages).
> >
> > Patch attached.
> 
> This strikes me as too clever by half.  You've introduced the concept
> of a "Browne strength" (apparently named for Christopher Browne) and
> yet you haven't even bothered to add a comment explaining the meaning
> of the term, let along justifying the choice of that formula rather
> than any other.  I don't want to dog this proposal to death, because
> surely we can do better than the status quo here, but adopting the
> first formula someone proposed without any analysis of whether it does
> the right thing cannot possibly be the correct decision process.

My intention was to apply a Nasby correction to Browne Strength and call
the resulting function Browne' (Browne prime).  Does that sound better?

Now seriously, I did experiment a bit with this and it seems to behave
reasonably.  Of course, there might be problems with it, and I don't
oppose to changing the name.  "Vacuum strength" didn't sound so great,
so I picked the first term that came to mind.  It's not like picking
people's last names to name stuff is a completely new idea; that said,
it was sort of a joke.

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


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Next:From: Christopher BrowneDate: 2013-01-31 20:28:58
Subject: Re: autovacuum not prioritising for-wraparound tables
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