From: Connor McDonald Newsgroups: comp.databases.oracle.misc Subject: Re: Magic number ( 5 * DB_BLOCK_SIZE ) Date: Wed, 06 Jun 2001 18:32:55 +0100 Organization: Budget Internet Lines: 33 Message-ID: <3B1E6947.1C0A@yahoo.com> References: <9fifqa$oct$1@venus.telepac.pt> NNTP-Posting-Host: 62.172.35.94 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: news.chatlink.com 991849246 13491 62.172.35.94 (6 Jun 2001 17:40:46 GMT) X-Complaints-To: abuse@chatlink.com NNTP-Posting-Date: 6 Jun 2001 17:40:46 GMT X-Mailer: Mozilla 3.01 (Win95; I) Jonas M wrote: > > Hi > > While studying by Oracle Books , I've come accross this tip several times: > > you should use uniform extent sizes : multiples of 5 * DB_BLOCK_SIZE > > Why do they insist on this value ? I thought the ideal situation would be to > fit all my data ( from a regular table ) in just one extent... > isn't that so ? Is it better to have several extents , and get the data > spread among them ? > > Thanx in advance Oracle rounds sizes to this multiple... although I'm a fan of making all extents a multiple of the max single OS read size (typically in the order of 128-256k). One thing I cannot stress enough is that "one extent" is a myth. What you want to have is all extents the same size (per tablespace that is). Check out locally managed tablespaces for some more info. hth connor -- ============================== Connor McDonald http://www.oracledba.co.uk "Some days you're the pigeon, some days you're the statue..."