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

From Tom Lane
Subject Re: Clock sweep not caching enough B-Tree leaf pages?
Date
Msg-id 20593.1397761783@sss.pgh.pa.us
Whole thread Raw
In response to Re: Clock sweep not caching enough B-Tree leaf pages?  (Stephen Frost <sfrost@snowman.net>)
Responses Re: Clock sweep not caching enough B-Tree leaf pages?  (Stephen Frost <sfrost@snowman.net>)
List pgsql-hackers
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.
        regards, tom lane



pgsql-hackers by date:

Previous
From: Merlin Moncure
Date:
Subject: Re: Clock sweep not caching enough B-Tree leaf pages?
Next
From: Stephen Frost
Date:
Subject: Re: Clock sweep not caching enough B-Tree leaf pages?