Re: Configuring fdatasync for Solaris2

Wow!  That is a huge difference.  I wish we could make
fdatasync/datasync use automatic.  We can't now because sometimes
fdatasync is just a stub for fsync, and in those cases open_fsync may be
a better option.  I would really like some ideas on automatic
configuration.


> > Date: Wed, 12 Sep 2001 14:19:09 +0200 (CEST)
> > From: Peter Eisentraut <peter_e@gmx.net>
> > To: Kenji Sugita <sugita@sra.co.jp>
> > Subject: Re: [PATCHES] Configuring fdatasync for Solaris2
> >
> > > I also cannot find out the rt library on Solaris2. The library posix4 hits
> > > fdatasync.
> >
> > I rechecked the manuals, apparently -lrt was added in a later version
> > (after the POSIX.4 group was renamed?).  I've changed the test to check
> > both libraries.
>
> Thanks a lot.
>
> > Do you have any performance data of the fdatasync method versus the
> > default open_datasync method?
>
> I have the data for SPARC 500MHz Solaris2.6 running PostgreSQL 7.1.3.
>
>     #clients  open_datasync  fdatasync (TPC-B, TPS)
>     ========  =============  =========
>     1             34.867522  47.188265
>     2             41.457329  57.119142
>     4             41.854741  62.250403
>     8             43.103382  63.909396
>     16            35.890254  62.757908
>     32            41.421592  52.132258
>     64            37.325511  51.805046
>     128           28.906521  37.942672
>
> This table is made by following commands:
>
>     pgbench -i -s 10
>     pgbench -c #clients -t 100
>
> > Peter Eisentraut   peter_e@gmx.net   http://funkturm.homeip.net/~peter
>
>
> Kenji Sugita
> sugita@sra.co.jp
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: if posting/reading through Usenet, please send an appropriate
> subscribe-nomail command to majordomo@postgresql.org so that your
> message can get through to the mailing list cleanly
>

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026