Re: Automatic Space Management Observation
- From: "Jonathan Lewis" <jonathan@xxxxxxxxxxxxxxxxxx>
- To: "Oracle-L" <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 17 Dec 2004 15:54:21 -0000
I think you must mean ASSM - Automatic Segment Space Management.
The 1MB as default switching to 8MB after 64 extents
isn't really to do with ASSM, though, it's a side-effect
of using locally managed tablespaces with 'autoallocate'
for extent sizing rather than 'uniform size'.
In this case, the normal behaviour pattern is 16 x 64K
extents before switching to 1MB extents, but if you're
importing large objects with a large 'initial' size, or
if your DDL requests a large initial size, then Oracle can
skip the smaller size extents and leap straight in to 1MB,
or even 8M extents.
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/seminar.html
Optimising Oracle Seminar - schedule updated Sept 19th
----- Original Message -----
From: "Mercadante, Thomas F" <thomas.mercadante@xxxxxxxxxxxxxxxxx>
To: "Oracle-L" <oracle-l@xxxxxxxxxxxxx>
Sent: Friday, December 17, 2004 2:55 PM
Subject: Automatic Space Management Observation
All,
I finally turned ASM on in my 9.2 database. The tablespaces were created
with no defaults - no uniform extent sizes.
Oracle created the tables all with 1M extent size. When loading a table, I
notice that the first 64 extents were all 1M in size. The last 9 extents
are all 8M in size.
So, is this how ASM works? Just curious if anyone else has had similar or
different experiences?
Thomas Mercadante
Oracle Certified Professional
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