Re: Clock sweep not caching enough B-Tree leaf pages? - Mailing list pgsql-hackers

From Stephen Frost
Subject Re: Clock sweep not caching enough B-Tree leaf pages?
Date
Msg-id 20140417191730.GQ2556@tamriel.snowman.net
Whole thread Raw
In response to Re: Clock sweep not caching enough B-Tree leaf pages?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
* Tom Lane (tgl@sss.pgh.pa.us) wrote:
> Stephen Frost <sfrost@snowman.net> writes:
> > I wonder if it would help to actually tell the OS to read in buffers
> > that we're *evicting*...  On the general notion that if the OS already
> > has them buffered then it's almost a no-op, and if it doesn't and it's
> > actually a 'hot' buffer that we're gonna need again shortly, the OS will
> > have it.
>
> But if it's actually gone cold, you're just forcing unnecessary read I/O,
> not to mention possibly causing something slightly warmer to be lost from
> kernel cache.

Certainly possible- see the email I just sent about another thought
around this.

Obviously, none of these thoughts are really fully formed solutions and
are, instead, just speculation and ideas.
Thanks,
    Stephen

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