Re: -F option, RAM usage, more... - Mailing list pgsql-general

From Neil Conway
Subject Re: -F option, RAM usage, more...
Date
Msg-id 20001004162402.A19300@klamath.dyndns.org
Whole thread Raw
In response to -F option, RAM usage, more...  ("Mike Biamonte" <mike@dbeat.com>)
List pgsql-general
On Wed, Oct 04, 2000 at 02:09:47PM -0400, Mike Biamonte wrote:
> I understand from the docs that -F ".. prevents fsync()'s from
> flushing to disk after every transaction.." and that this boosts
> performance because RAM accesses are far faster than disk accesses.  I
> have also seen some impressive stats regarding the degree of this
> performance boost.

Correct me if I'm wrong, but I believe that when you specify '-F', it
allows the filesystem to buffer I/O operations, performing several
operations once after another. This is much faster than with fsync(),
where the disk heads have to be moved frequently. Also, allowing the
I/O subsystem to buffer some data will speed subsequent accesses of it,
until the buffer is flushed.

HTH,

Neil

--
Neil Conway <neilconway@home.com>
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