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RE: Locally Managed Tablespaces - Questions.

From: Jacques Kilchoer <>
Date: Tue, 15 Apr 2003 16:33:51 -0800
Message-ID: <>

A possible justification for using autoextend was mentioned on the list recently.

You have a table whose growth you cannot predict. Put it in an autoextend tablespace so that you won't end up with an unwieldy number of extents. Though of course people have shown recently on the list that in a locally managed tablespace, dropping a table with a very large number of extents (which was one of my objections to a very large number of extents) doesn't seem to take very long. But Steve Adams does mention in his "planning extents" article ( ) : "we recommend that the number of extents per segment in locally managed tablespaces be limited to the number of rows that can be accommodated in the extent map within the segment header block - that is, approximately (db_block_size / 16) - 7."

Another reason - one of the software products that I help develop asks the user to select a tablespace to install a repository of objects needed by our product. Some of those objects will be very small, and some have the potential of becoming very large. I don't want to have to ask the user to choose 2 or 3 different tablespaces at install time. So an autoallocate tablespace would be a good solution.

> -----Original Message-----
> From: []
> Tom is a very bright guy.
> Can't say I always agree with him though. This is
> one of those instances.
> In this article he refers to 335 extents being 'well within the
> bounds of reason'. There are other places where he
> states that the number of extents doesn't matter.
> Are there any good reasons for using autoallocate?

Please see the official ORACLE-L FAQ:
Author: Jacques Kilchoer

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Received on Tue Apr 15 2003 - 19:33:51 CDT

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