Re: [PATCHES] ARC Memory Usage analysis

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От Tom Lane
Тема Re: [PATCHES] ARC Memory Usage analysis
Дата
Msg-id 18764.1098477951@sss.pgh.pa.us
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Ответ на Re: ARC Memory Usage analysis  (Jan Wieck <JanWieck@Yahoo.com>)
Ответы Re: [PATCHES] ARC Memory Usage analysis  (Simon Riggs <simon@2ndquadrant.com>)
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Jan Wieck <JanWieck@Yahoo.com> writes:
> What do you think about my other theory to make C actually 2x effective
> cache size and NOT to keep T1 in shared buffers but to assume T1 lives
> in the OS buffer cache?

What will you do when initially fetching a page?  It's not supposed to
go directly into T2 on first use, but we're going to have some
difficulty accessing a page that's not in shared buffers.  I don't think
you can equate the T1/T2 dichotomy to "is in shared buffers or not".

You could maybe have a T3 list of "pages that aren't in shared buffers
anymore but we think are still in OS buffer cache", but what would be
the point?  It'd be a sufficiently bad model of reality as to be pretty
much useless for stats gathering, I'd think.

            regards, tom lane

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