Message-ID: <4C6C2E4A.1010506@agliodbs.com>
Date: Wed, 18 Aug 2010 12:02:34 -0700
From: Josh Berkus <josh@agliodbs.com>
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To: Tom Lane <tgl@sss.pgh.pa.us>
CC: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Return of the Solaris vacuum polling problem -- anyone
	remember this?
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> On further reflection, though: since we put in the BufferAccessStrategy
> code, which was in 8.3, the background writer isn't *supposed* to be
> very much involved in writing pages that are dirtied by VACUUM.  VACUUM
> runs in a small ring of buffers and is supposed to have to clean its own
> dirt most of the time.  So it's wrong to blame this on the bgwriter not
> holding up its end.  Rather, what you need to be thinking about is how
> come vacuum seems to be making lots of pages dirty on only one of these
> machines.

This is an anti-wraparound vacuum, so it could have something to do with
the hint bits.  Maybe it's setting the freeze bit on every page, and
writing them one page at a time?  Still don't understand the call to
pollsys, even so, though.

-- 
                                  -- Josh Berkus
                                     PostgreSQL Experts Inc.
                                     http://www.pgexperts.com