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02-23-2008, 05:23 AM
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 ASSM worth it? We are getting ready to upgrade from 8i to 9i. Since we have over 300GB, there may be no time to do an export/import; therefore, we are considering using the migration tool to upgrade in place. If we do the upgrade in place, we will not get the 9i enhancement ASSM (auto segment space management). Any thoughts on the downside of this? Thanks.      |
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02-23-2008, 05:24 AM
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| Re: ASSM worth it? "TomT" <dontspam@spam.com> wrote in message news:<7P0Eb.24$Nk4.25847@news.uswest.net>... > We are getting ready to upgrade from 8i to 9i. Since we have over 300GB, > there may be no time to do an export/import; therefore, we are considering > using the migration tool to upgrade in place. If we do the upgrade in > place, we will not get the 9i enhancement ASSM (auto segment space > management). Any thoughts on the downside of this? Thanks. Do you have segment header contention? Do you have multiple freelists of freelist_groups defined? This article might help: http://builder.com.com/5102-6388-5031994.html |
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02-23-2008, 05:25 AM
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| Re: ASSM worth it? If your tables' physical structure is well configured and performing for freelists, there's no reason for going with ASSM, especially if you're not using RAC. Tanel. "TomT" <dontspam@spam.com> wrote in message news:7P0Eb.24$Nk4.25847@news.uswest.net... > We are getting ready to upgrade from 8i to 9i. Since we have over 300GB, > there may be no time to do an export/import; therefore, we are considering > using the migration tool to upgrade in place. If we do the upgrade in > place, we will not get the 9i enhancement ASSM (auto segment space > management). Any thoughts on the downside of this? Thanks. > > |
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02-23-2008, 05:25 AM
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| Re: ASSM worth it? I wouldn't bother at present - the concept is quite nice, but there are still (9.2.0.4) a few nasty implementation features (bugs even) in ASSM which can have serious side-effects on space management or performance. (See http://www.jlcomp.demon.co.uk/bustbits.html for a particularly amusing example - still fails in 9.2.0.4 but fixed in 10.1). If you execute very large numbers of small insert statements with a high degree of concurrency, then ASSM could cause significant latching problems. If you currently set PCTFREE to anything in excess of 75 (which would be a little unusual, notwithstanding the comment in the article referenced by Geomancer) then you it is possible to get severely burned on space wastage on deletes. -- Regards Jonathan Lewis http://www.jlcomp.demon.co.uk The educated person is not the person who can answer the questions, but the person who can question the answers -- T. Schick Jr One-day tutorials: http://www.jlcomp.demon.co.uk/tutorial.html Three-day seminar: see http://www.jlcomp.demon.co.uk/seminar.html ____UK___November The Co-operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.html "TomT" <dontspam@spam.com> wrote in message news:7P0Eb.24$Nk4.25847@news.uswest.net... > We are getting ready to upgrade from 8i to 9i. Since we have over 300GB, > there may be no time to do an export/import; therefore, we are considering > using the migration tool to upgrade in place. If we do the upgrade in > place, we will not get the 9i enhancement ASSM (auto segment space > management). Any thoughts on the downside of this? Thanks. > > |
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