Re: O_DIRECT - Mailing list pgsql-hackers

From Zeugswetter Andreas SB SD
Subject Re: O_DIRECT
Date
Msg-id 46C15C39FEB2C44BA555E356FBCD6FA41EB39A@m0114.s-mxs.net
Whole thread Raw
In response to O_DIRECT  ("Christopher Kings-Lynne" <chriskl@familyhealth.com.au>)
List pgsql-hackers
> > 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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