Re: Automatic Space Management Observation

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_at_labor.state.ny.us> To: "Oracle-L" <oracle-l_at_freelists.org> 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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http://www.freelists.org/webpage/oracle-l Received on Fri Dec 17 2004 - 09:50:06 CST