From oracle-l-bounce@freelists.org Wed Dec 22 08:39:12 2004 Return-Path: Received: from air189.startdedicated.com (root@localhost) by orafaq.com (8.11.6/8.11.6) with ESMTP id iBMEdCQ10579 for ; Wed, 22 Dec 2004 08:39:12 -0600 X-ClientAddr: 206.53.239.180 Received: from turing.freelists.org (freelists-180.iquest.net [206.53.239.180]) by air189.startdedicated.com (8.11.6/8.11.6) with ESMTP id iBMEdCN10574 for ; Wed, 22 Dec 2004 08:39:12 -0600 Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id E2F0672C2B2; Wed, 22 Dec 2004 09:45:41 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 21949-32; Wed, 22 Dec 2004 09:45:41 -0500 (EST) Received: from turing (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id A335772CBFE; Wed, 22 Dec 2004 09:43:19 -0500 (EST) Message-ID: <029a01c4e83d$4ec13330$0100000a@FOOTE> From: "Richard Foote" To: "Active DBA" Cc: References: <97b7fd2f04122102523a83f730@mail.gmail.com> <97b7fd2f0412212312759f6893@mail.gmail.com> <1103701045.8656.83.camel@bobak.net> <687bf9c404122200294647f6ce@mail.gmail.com> Subject: Re: is rebuilding indexes necessary after import? Date: Thu, 23 Dec 2004 01:45:47 +1000 MIME-Version: 1.0 Content-type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-archive-position: 14026 X-ecartis-version: Ecartis v1.0.0 Sender: oracle-l-bounce@freelists.org Errors-To: oracle-l-bounce@freelists.org X-original-sender: richard.foote@bigpond.com Precedence: normal Reply-To: richard.foote@bigpond.com X-list: oracle-l X-Virus-Scanned: by amavisd-new at freelists.org Comments below ----- Original Message ----- From: "stephen booth" To: Cc: ; "Active DBA" Sent: Wednesday, December 22, 2004 6:29 PM Subject: Re: is rebuilding indexes necessary after import? On Wed, 22 Dec 2004 02:37:25 -0500, Mark J. Bobak wrote: > No, because import does not really "import" indexes. It issues a create > index statement. So, the indexes are freshly built at the end of an > import. > -Mark That begs the question, when is the create index statement issued? 'Create table, create index, import rows' and 'create table, import rows, create index' could lead to different results in terms of index efficiency. If the order of the data is such that the leading edge of the index is monotonically increasing or decreasing then you'll probably get an unbalanced and inefficient index (the same as you do with any increasing indexed value) if the index is created before the before the rows are imported and isn't reverse key. Hi Stephen, Monotonically increasing indexes do not become unbalanced and in the vast majority of cases, don't become inefficient. Please take a look at : http://www.actoug.org.au/Downloads/oracle_index_internals.pdf One day, the message will get through. One day ... Cheers Richard -- http://www.freelists.org/webpage/oracle-l