Re: VACUUM and spoiling the buffer manager cache

On Thu, 2007-03-01 at 11:00 +0900, ITAGAKI Takahiro wrote:
> "Simon Riggs" <simon@2ndquadrant.com> wrote:
> 
> > > > VACUUM's current behaviour is to take blocks it has touched and place
> > > > them on the head of the freelist, allowing them to be reused.
> > > 
> > > No, it puts them at the tail of the freelist.
> > 
> > That's a minor point because the freelist is mostly empty, so head ==
> > tail in 99.9% of cases.
> 
> That's correct. Also, even if a VACUUM process collects some unused buffers
> into the freelist, other backends comsume all of them in a moment.

AFAICS the patch is useful and valid. 

Please could we have some additional testers, so that we have a range of
opinion, rather than just my/EDB tests.

I'll submit further detailed tests after feature freeze, since right now
I have other things to do, but I'll return to this point again.

--  Simon Riggs              EnterpriseDB   http://www.enterprisedb.com