From: Geert De Paep Subject: Re: understanding RBS - Guidelines Date: 1997/05/05 Message-ID: <336D8952.B19@cimad.be>#1/1 References: <5jkuhe$o9g@dns.camcnty.gov.uk> <5k1tk9$gcg@dns.camcnty.gov.uk> <5k2ooq$p22@dns.camcnty.gov.uk> <3365ADD2.68B9@cimad.be> <5k4gtv$9r6@dns.camcnty.gov.uk> <33670A28.3A21@cimad.be> <336a2f31.4808134@nntp.peg.apc.org> To: Steve Adams Organization: Cimad Consultants Reply-To: gdp@cimad.be Newsgroups: comp.databases.oracle.server Steve, According to me, 10 extents should be enough. This number will not influence the space usage of an extent, as every new transaction takes a new oracle block, independent of the number of blocks in an extent or the number of extents. Wrapping around is no significant cost either. A serious cost however is (de)allocating extents! The optimal size of your rbs is determined by the activity you do (the length of your transactions). So the more extents you take, the smaller they will be for a given total rbs-size. If from time to time the transaction is longer and the rbs has to grow, you better have your extents not too small, because for small extents you will have to allocate more of them. And as the previous paragraph said, allocating extents is costly. Less than 10 extents is not recommended either, because in that case the chance of having to allocate extra extents (growing rbs) becomes bigger. So I think 10 is ok, 5 or 15 could still be alright, but I (personally) would not go over 20 or 30. Geert. -- A psychiatrist is a person who will give you expensive answers that your wife will give you for free. ______ ______ __ __ _____ ____ Geert De Paep / ____/ __ __/ / __ / __ | Cimad Consultants / / / /|_/ / /_ / / / Groenenborgerlaan 16 / / / / / __ / / / 2610 Antwerpen /_____/ ______/ __/ __/ __/ __/ _____/ http://www.cimad.be Email: gdp@cimad.be Tel: 03/820 82 50