Re: scattered reads

From: Tanel Poder <tanel.poder.003_at_mail.ee>
Date: Tue, 3 Feb 2004 19:42:08 +0200
Message-ID: <035b01c3ea7d$0c88a840$eafb23d5@porgand>

Maybe you have analyzed your data dictionary by accident (or haven't set optimizer* parameters accordingly) and your query uses full table scans on underlying tables extensively.

Btw, select * from dba_segments in a fully LMT 9i requires multiple IOs for each segment header blocks as well, in order to determine number of blocks & extents in it (seg$ contains obsolete information)

Tanel.

Original Message ----- From: "Kommareddy, Srinivas (MED, Wissen Infotech)" <Srinivas.Kommareddy_at_med.ge.com> To: <oracle-l_at_freelists.org> Sent: Tuesday, February 03, 2004 9:28 AM Subject: scattered reads

> Hi Gurus,
>
> DB: 9.2x
> OS: solaris 2.8
>
> Why the following query is waiting for db file scattered reads....
>
> select segment_name from dba_segments
> where tablespace_name in
> ('ASPD',
> 'CSED',
> 'CUED',
> 'DDDD' ..... 50 more tablespaces.
>
> What could be done to avoid this db file scattered reads ?
>
> Is there a better way to get this.
>
>
> Thanks and Regards,
> Srinivas
> Oracle DBA ( ODC )
> Wissen Infotech Pvt. Ltd.
> Hyderabad, India
> Work +91-40-55313031, 91-40-27892897
> e-mail Srinivas.Kommareddy_at_med.ge.com
> Visit us http://www.wisseninfotech.com <http://www.wisseninfotech.com>
>
>
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Received on Tue Feb 03 2004 - 11:42:08 CST