On 4/8/09 9:44 AM, Tom Lane wrote:
Josh Berkus<j...@agliodbs.com>  writes:
What about seq scans?

If the kernel can't read-ahead a seqscan by itself, it's unlikely to
be smart enough to be helped by posix_fadvise ... or at least so I
would think.  Do you have reason to think differently?

Well, Solaris 10 + UFS should be helped by fadvise -- in theory at least, it would eliminate the need to modify your mount points for better readahead when setting up a PG-Solaris server. Solaris-UFS quite lazy about readahead. Zdenek, Jignesh?

You're probably correct about Linux and FreeBSD. I don't know if OSX + HFS supports fadvise. If so, it could only help; readahead on HFS right now is nonexistant.

Presumably fadvise is useless on Windows.  Anyone know?


--
Josh Berkus
PostgreSQL Experts Inc.
www.pgexperts.com

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