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 -- //www.freelists.org/webpage/oracle-l -- //www.freelists.org/webpage/oracle-l