Re: Return of the Solaris vacuum polling problem -- anyone remember this?

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(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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