Oracle-L: RE: Initial Extent 5GB?? for 17GB table!!

From: Hately Mike <Mike.Hately_at_churchill.com>
Date: Tue, 06 Aug 2002 09:33:38 -0800
Message-ID: <F001.004AC51F.20020806093338@fatcity.com>

Peter,
this is just off the top of my head but very roughly I'd do this:

Reverse engineer any indexes.

Create your new tablespace (on a separate physical disk/disks) if possible.

CREATE TABLE new_table
STORAGE ( )
TABLESPACE new_tablespace
AS SELECT * FROM old_table
NOLOGGING; Drop any indexes or constraints on the old table.

Drop (or rename) the old table.

Create the constraints and indexes on the new table.

You may see a performance gain but I'm wary of predicting anything. It will depend on the pattern of population and deletes and the access patterns for the data. And even then I'll probably be way off the mark =)

Given that there's no appreciable difference in having 1 or 100 extents I'd give the new table an initial and next extent of under 2GB.

Regards,
Mike Hately

-----Original Message-----
Sent: 06 August 2002 17:54
To: Multiple recipients of list ORACLE-L

Hi Friends,

I have GL table ready to reorg! The table underwent so many purges, Now had real data 17Gb with initial and next extents as 360M, Offcourse the total size showing 26Gb from dba_segments. I want to avoid export and Import process due to time taking.

I want to use CTAS to reorg this GL table.

First Create a copy of GL in Newtablespace Drop main GL table
Creat New GL table with new storage parameters like Initial extent 5GB(I knew I had more than 10Gb data!!) and next extent 360M, and pctused 40, pctfree 5.
Insert data from copy GL to Main GL and create all indexes

My doubts are Can I create such a big Initial extent?? What other implications I may face in future? Will it increase performance?? I can't create newtablespace for this table due to my system already saturated in terms of diskspace.
My environment is oracle7.3 on AIX, btw my avg row length is 448 bytes. MY aim is simple! To pack the data and get back space!!

Thanks in advance for your help
peter.

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Author: Hately Mike
INET: Mike.Hately_at_churchill.com

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