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RE: Autoallocate vs Uniform extent performance

From: Jacques Kilchoer <Jacques.Kilchoer_at_quest.com>
Date: Thu, 03 Apr 2003 19:08:48 -0800
Message-ID: <F001.0057A14C.20030403190848@fatcity.com>


I get the impression from what I've read on this list and elsewhere that in general one shouldn't worry about the number of extents in a table, at least for full table scans. (It can become a problem when dropping a table - at least in a dictionary managed tablespace - though as I know from experience.)

For locally managed tablespaces, the only word of caution I've read is from the Ixora website
Planning extents
http://www.ixora.com.au/tips/creation/extents.htm "... 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."

> -----Original Message-----
> From: Richard Foote [mailto:richard.foote_at_telstra.com]
>
> Just a general question to everyone (and one I've asked a few times
> before in different forums).
>
> If we're talking LMT, how many extents are too many ?
> ...

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Jacques Kilchoer
  INET: Jacques.Kilchoer_at_quest.com

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Received on Thu Apr 03 2003 - 21:08:48 CST

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