RE: comments on forcedirectio

Zhu

The Batch Jobs suffered most though there was a Database wide slow down too. This happened years ago, hence memory is faint.

You seem to have given a good explanation -> "Batch job can be slower as now filesystem cache does not cache the data that not cached by oracle SGA when you do full table scan"

All other parameters remained unchanged & RAM memory was NOT a constraint on the E10K SUN machine.

HTH -----Original Message-----
From: zhu chao [mailto:zhuchao_at_gmail.com]=20 Sent: Thursday, May 05, 2005 5:27 PM
To: VIVEK_SHARMA
Cc: geraldine_2_at_comcast.net; oracle-l_at_freelists.org Subject: Re: comments on forcedirectio

Hi, Vivek,

    Is it only batch job related application slow down, or really the WHOLE instance slowed down? Batch job can be slower as now filesystem cache does not cache the data that not cached by oracle SGA when you do full table scan.

    After you changed the from buffered io to forcedirectio, do you have any change in oracle SGA size? As now more free memory can be used by oracle?

On 5/4/05, VIVEK_SHARMA <VIVEK_SHARMA_at_infosys.com> wrote: >=20
> We experienced significant database wide slowdown for a High
Transaction
> volume Hybrid(OLTP+Batch) type database on setting
forcedirectio(Solaris
> OS) on datafile's partitions with Oracle 8i. Performance returned to
> normal on removal of the same.

>=20
> HTH
--=20
Regards
Zhu Chao
www.cnoug.org

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