Rob Wultsch wrote:
> For a documentation patch should this not be back ported to all
> relevant versions?
It is only a minor adjustment and I normally don't backpatch that.
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>
> On 8/21/10, Bruce Momjian <bruce@momjian.us> wrote:
> > Josh Berkus wrote:
> >>
> >> > 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.
> >
> > We often mention that we do vacuum freeze for anti-wraparound vacuum,
> > but not for pg_clog file removal, which is the primary trigger for
> > autovacuum vacuum freezing. I have added the attached documentation
> > patch for autovacuum_freeze_max_age; back-patched to 9.0.
> >
> > --
> > Bruce Momjian <bruce@momjian.us> http://momjian.us
> > EnterpriseDB http://enterprisedb.com
> >
> > + It's impossible for everything to be true. +
> >
>
>
> --
> Rob Wultsch
> wultsch@gmail.com
-- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB
http://enterprisedb.com
+ It's impossible for everything to be true. +