Re: Oh Where Oh Where Is My Redo Coming From

Which version of Oracle ?

Has someone switched on supplemental logging at the database level, perhaps ?

Have you got dbms_job kicking in every 5 seconds with job_queues set to 10 ? (Honest, I have seen it happen, and the effect on redo was astonishing - and there was only one job actually ever available to run).

Does the application use lots of transient tables which it fills and then deletes / rolls back.

Is the volume of redo very much larger than the volume of UNDO, as this may indicate table creation, index rebuilds, mass inserts rather than update activity (which would tend to leave the redo in the ballpark of double the undo).

Are there any files with an extreme number of writes (other than temporary tablespace files of course) - as you might want to track the objects in those files rather than trying to monitor the whole database.

Are there any files with lots of multiblock writes - (apart from temp) as this tends to indicate table moves, index rebuilds, as well as direct mode inserts.

Regards

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

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The Co-operative Oracle Users' FAQ
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-----Original Message-----
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> Date: 21 February 2003 17:35

>Just had a thought here, have not tried it yet. I have a database
that I am
>working with that is generating 28 GB of redo each day. I would
really like
>to know what objects are generating all this redo without going
through the
>hassle of mining a bunch of log files. It occurred to me that if
table
>monitoring is active and my stats are up to date I should be able to
>multiply the total number of updates, inserts and commits by the
average row
>size and get a rough % of what objects are generating the most redo.
>
>I am sure there are a number of other factors I need to consider, any
ideas
>what they are?
>also send the HELP command for other information (like subscribing).
>

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Author: Jonathan Lewis
  INET: jonathan_at_jlcomp.demon.co.uk

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