Re: O_DIRECT

From: "Zeugswetter Andreas SB SD" <ZeugswetterA(at)spardat(dot)at>
To: "Bruce Momjian" <pgman(at)candle(dot)pha(dot)pa(dot)us>
Cc: "Hackers" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: O_DIRECT
Date: 2001-10-01 12:15:16
Message-ID: 46C15C39FEB2C44BA555E356FBCD6FA41EB39A@m0114.s-mxs.net
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> > The O_DIRECT flag has been added to open(2) and fcntl(2). Specifying
this
> > flag for open files will attempt to minimize the cache effects of
reading
> > and writing.
>
> I wonder if using this for WAL would be good.

Not before the code is not optimized to write more than the current 8k
to
the WAL at a time.
(The killer currently are larger transactions that produce approx more
than 64k WAL, (try the open_datasync setting with "copy from"))

Andreas

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