RE: Oracle 7.3.4 problem... SLOW Drop user
- From: "Cary Millsap" <cary.millsap@xxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 4 Aug 2004 12:16:18 -0500
The one thing that is slow when a dictionary-managed segment has lots of
extents is DROP. To enable recoverability, DROP works this way:
while exists(extent) {
seek to the end of the extent list
drop the final extent
}
The problem is that this algorithm is O(n^2). A 100-extent table will =
take
100^2 =3D 10,000x longer to drop than a 1-extent table. A 1,000-extent =
table
will take 100x longer to drop than a 100-extent table (or a million =
times
longer than a 1-extent table).
With locally-managed segments, this is no longer a problem. So, part 2 =
of
your solution is that when you rebuild your schema, use locally-managed
tablespaces if you can.
Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com
* Nullius in verba *
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-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx =
[mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of GUPTA, DEEPENDER
Sent: Wednesday, August 04, 2004 11:59 AM
To: 'oracle-l@xxxxxxxxxxxxx'
Subject: RE: Oracle 7.3.4 problem... SLOW Drop user
Truncate all the tables and then try it..
Deep
-----Original Message-----
From: Denham Eva [mailto:EVAD@xxxxxxxxxx]=20
Sent: Wednesday, August 04, 2004 11:02 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: Oracle 7.3.4 problem... SLOW Drop user
Hello Folks,
=20
We have a legacy system on Oracle 7.3.4 on NT.=20
I am dropping the user with cascade, but it is extremely slow???
About 2GB in 5hrs? and there are still 10GB to go.
=20
Can anyone tell me why? Can I stop it and restart it for beter
performance?
=20
I am doing the drop from a client machine, could this be the problem?
=20
Any help would be appreciated!
Denham
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