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Home -> Community -> Mailing Lists -> Oracle-L -> Re: filesystemio_options option on solaris 9 sparc 64-bit (Oracle 10g)
AFAIK it depends on OS, in Linux for example by default it tries to cache
everything (you can tweak some kernel parameters), in HP-UX its determined
by dbc_max_pct kernel parameters. Solaris you need to google :-(
Your test would be using SAME SGA, create a table in a Filesystem without DIO and create same table in another filesystem with DIO. Preferably one tablespace per table. Flush buffer cache to ensure nothing is cached, run FTS on first table 3 or 4 times, flush buffer cache again and repeat the FTS with second table.
If you cannot afford flush the whole buffer cache then take the tablespaces offline and online would do.
Thanks
-- LSC On Nov 21, 2007 12:37 PM, DBA Deepak <oracle.tutorials_at_gmail.com> wrote:Received on Wed Nov 21 2007 - 05:45:12 CST
> Thanks LS for your pointer. But have one question. Is the file system
> buffer big enough to cache large table's data, so that FTS of large
> tables will be faster?
>
> How to know how big is the file system's cache?
>
> Deepak
>
>
>
> On Nov 21, 2007 4:45 PM, LS Cheng <exriscer_at_gmail.com> wrote:
> > Hi
> >
> > I shall point you to a ML note 462072.1 which talks about Linux but the
> > theory applies for other UNIX flavours as well.
> >
> > I had recent experience with DIO in AIX, the database actually went
> worse
> > when DIO was enabled it was because the application did many full table
> > scans even though I doubled buffer cache.
> >
> > Thanks
> >
> > --
> > LSC
> >
> >
> >
> >
> >
> > On Nov 21, 2007 12:01 PM, DBA Deepak <oracle.tutorials_at_gmail.com> wrote:
> > > Hi LS,
> > >
> > > Can you please help me in understanding how direct i/o will make the
> > > FTS of a big table slower?
> > >
> > > If FTS becomes slow then is it not recommended to use directio where
> > > FTS of large tables are done?
> > >
> > > As per many experts we should always use directio+ufs combination for
> > > oracle files related disks.
> > >
> > > Deepak
> > >
> > >
> > >
> > >
> > > On Nov 21, 2007 4:08 PM, LS Cheng < exriscer_at_gmail.com> wrote:
> > > > one option is brute force :-P
> > > >
> > > > create a very big table and full scan it, direct i/o will be slower
> > because
> > > > filesystem buffer would help in this case!
> > > >
> > > > --
> > > > LSC
> > > >
> > > >
> > > >
> > > >
> > > > On Nov 21, 2007 10:11 AM, DBA Deepak < oracle.tutorials_at_gmail.com>
> > wrote:
> > > > >
> > > > >
> > > > >
> > > > > Hi John,
> > > > >
> > > > > Sorry for the late response. Even after mounting the filesystem
> with
> > > > > "forcedirectio" option am unable to see a non-zero value as the
> third
> > > > > parameter value to the ioctl() calls. I did the same experiment as
> > > > > mentioned in your previous mail.
> > > > >
> > > > > Would you please tell is there any alternative to verify whether
> the
> > > > > system is using directio or not?
> > > > >
> > > > > Regards,
> > > > >
> > > > > Deepak
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > On Oct 18, 2007 12:45 PM, John Hallas < john.hallas_at_bjss.co.uk>
> wrote:
> > > > > >
> > > > > >
> > > > > >
> > > > > > Have the filesystems been mounted with direct_io option?
> > > > > >
> > > > > >
> > > > > > ________________________________
> > > > > >
> > > > > >
> > > > > > From: oracle-l-bounce_at_freelists.org
> > > > [mailto:oracle-l-bounce_at_freelists.org ]
> > > > > > On Behalf Of DBA Deepak
> > > > > > Sent: 17 October 2007 19:39
> > > > > > To: John Hallas
> > > > > > Cc: oracle-l
> > > > > > Subject: Re: filesystemio_options option on solaris 9 sparc
> 64-bit
> > > > (Oracle
> > > > > > 10g)
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > Hi John,
> > > > > >
> > > > > >
> > > > > >
> > > > > > Thanks for your help. In my environment filesystemio_options is
> set
> > to
> > > > > > SETALL
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > Still it is not using directIO as per your test. My server is
> sparc
> > > > Solaris
> > > > > > 9, 64 bit with Oracle 10.2.0.3.
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > Can you please help me in troubleshooting the same. Am I missing
> > > > anything?
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > ________________________________
> > > > > >
> > > > > > BJSS Limited, 1st Floor Coronet House, Queen Street, Leeds LS1
> 2TW.
> > > > > > Registered in England with company number 2777575.
> > > > > > http://www.bjss.co.uk
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > > >
> > > > > --
> > > > > Regards,
> > > > >
> > > > > Deepak
> > > > > Oracle DBA
> > > > > --
> > > > > http://www.freelists.org/webpage/oracle-l
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >
> > >
> > > --
> > > Regards,
> > >
> > > Deepak
> > > Oracle DBA
> > >
> >
> >
>
>
>
> --
> Regards,
>
> Deepak
> Oracle DBA
>
-- http://www.freelists.org/webpage/oracle-l
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