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Home -> Community -> Mailing Lists -> Oracle-L -> RE: 8.1.7 LMTs Autoallocate vs Uniform Extents
Sundeep
Oops, egg on my face. Reading too fast, seeing one word and thinking another. My understanding from "Stop Defragmenting and Start Living" was that uniform extents was the direction Oracle was heading. The problem with autoallocate is that you can end up with fragmented tablespaces and therefore have to reorganize them from time to time. You end up with free spaces of varying sizes. With uniform extents you can't have fragmentation because all the extents are exactly the same size. The down side is that you may waste a bit more space because a small table may have more space allocated than it needs. Also you must get beyond the myth that a good table is all in one extent. Based on the above, I opted for uniform extents and have been pleased with the results. However, if someone has some strong arguments for autoallocate, I would be interested in hearing them. Hopefully this time I have responded to your question. Let me know.
I went to http://www.google.com and searched for Oracle Autoallocate. Here is a link I found:
http://www.jlcomp.demon.co.uk/ch_08.html With autoallocate tablespaces, you may get a fairly random scattering of 64K, 1MB, 8MB or 64MB depending on the demand and the current state of the tablespace.
Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com
-----Original Message-----
Sent: Tuesday, March 26, 2002 2:46 PM
To: Multiple recipients of list ORACLE-L
Dennis,
I mentioned Autoallocate and not autoextend. I have been using LMTs for over a year now but only with UNIFORM extent sizes. I am not sure if I am ready to handover space management to Oracle (via Autoallocate which is being foisted upon me as a panecea of all ills) least I have evaluated the pros and cons. The stuff in Manual and technet I have reveiwed so far doesn't give you enough information like how much space is wated in Autoallocate vs Uniform extent sizes. How does Oracle decide to allocate an extent for an Insert or an Update in Autoallocate option and how does it decide on the extent size?
So far I have looked at SQLRef, Concepts manual and technet. Any other pointers?
TIA
Sundeep
Sundeep Maini
Consultant
Currently on Assignement at Marshfield Clinic WI
mainis_at_mfldclin.edu
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: sundeep maini INET: sundeep_maini_at_yahoo.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: DENNIS WILLIAMS INET: DWILLIAMS_at_LIFETOUCH.COM Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Tue Mar 26 2002 - 15:36:47 CST
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