Re: VACUUM and spoiling the buffer manager cache

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От ITAGAKI Takahiro
Тема Re: VACUUM and spoiling the buffer manager cache
Дата
Msg-id 20070301105503.5EA4.ITAGAKI.TAKAHIRO@oss.ntt.co.jp
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Ответ на Re: VACUUM and spoiling the buffer manager cache  ("Simon Riggs" <simon@2ndquadrant.com>)
Ответы Re: VACUUM and spoiling the buffer manager cache  ("Simon Riggs" <simon@2ndquadrant.com>)
Список pgsql-hackers
"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.

Regards,
---
ITAGAKI Takahiro
NTT Open Source Software Center




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