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RE: LMT monitoring

From: Ehresmann, David <>
Date: Mon, 10 Mar 2003 12:05:16 -0800
Message-ID: <>

If you read Jonathan Gennick's LMT article from the Nov/Dec 2000 Oracle Magazine he discusses the possible extent sizes, i.e. 64k, 1M, 8M, and finally 64M. <>  

David Ehresmann.

-----Original Message-----
Sent: Monday, March 10, 2003 1:26 PM
To: Multiple recipients of list ORACLE-L

>From my testing, I have found the following autoallocate alogrithm. The
first 16 extents are 64k in size. The subsequent allocation method is the next 63 extents of 1m, the next 120 extents of 8m and all additional extents at 64m. I have tested this with segments in excess of 100 gigabytes and I did not find a new extent size. The first 3 sizes are documented by Oracle, the last one I found by testing and have verified from other research, though the author/website escapes me at the current time.


Daniel W. Fink <> 

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Jamadagni, Rajendra wrote:


in case of auto allocate, oracle used 4 or 5 (experts don't even agree on if
it is 4 or 5) fixed sizes (64k ...) and based on number of existing extents
it will choose when an extent of next size should be allocated. The problem
is there is no set formula (or I haven't seen one agreed upon by Oracle ...
the answer from Oracle is always fuzzy about this).

That's why, I don't know if the next extent of my table will be 64K or 1M
... if someone knows a formula, I can write a quick script and things would
be easy ... but due to lack of formula, everything is a hypothesis ..

In case of dictionary managed, you have next extent size and pct increase
and you can predict what the next extent would be. This is also true if you
use uniformed extents in LMT. But it isn't easy in LMT and auto allocate. It
is probably as predictable as expecting a straight like from a drunken
monkey with a crayon.

Rajendra dot Jamadagni at espn dot com 
Any views expressed here are strictly personal. 
QOTD: Any clod can have facts, having an opinion is an art !! 


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Received on Mon Mar 10 2003 - 14:05:16 CST

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