Message-ID: <F001.0051EB06.20021219105545@fatcity.com>
Date: Thu, 19 Dec 2002 10:55:45 -0800
To: Multiple recipients of list ORACLE-L <ORACLE-L@fatcity.com>
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From: "Jonathan Lewis" <jonathan@jlcomp.demon.co.uk>
Subject: Re: 9i / 9iRAC : Segment_Space_Management AUTO, with LOB
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Depending on your circumstances, ASS Management
can eliminate severe contention on the freelists / freelist
groups area.  However, because Oracle is overgenerous
with its allocation of bitmap blocks (which may turn
out to be in excess of 1% of your database), you
may end up thrashing your system because most of
your buffer space is flooded with hot BMBs and the
data has to keep thrashing on and off disk.

Regards

Jonathan Lewis
http://www.jlcomp.demon.co.uk

Coming soon a new one-day tutorial:
Cost Based Optimisation
(see http://www.jlcomp.demon.co.uk/tutorial.html )

Next Seminar dates:
(see http://www.jlcomp.demon.co.uk/seminar.html )

____England______January 21/23


The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html


-----Original Message-----
To: Multiple recipients of list ORACLE-L <ORACLE-L@fatcity.com>
Date: 19 December 2002 17:51


>We were the other way around in our testing lately:-)
>
>We turned on auto space management to remove the contention.
Afterwards-we
>removed quite a bit of header block/free list contention..
>
>anyway, more tests to follow
>
>-----Original Message-----
>Sent: Thursday, December 19, 2002 10:09 AM
>To: Multiple recipients of list ORACLE-L
>
>
>
>As part of a RAC benchmark with 9.2 we had faced severe LOCKING
>on setting segment space management AUTO & had to REMOVE it
>
>HTH
>


-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Jonathan Lewis
  INET: jonathan@jlcomp.demon.co.uk

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