Path: text.usenetserver.com!out02b.usenetserver.com!news.usenetserver.com!in02.usenetserver.com!news.usenetserver.com!cycny01.gnilink.net!spamkiller2.gnilink.net!gnilink.net!trndny09.POSTED!cf34440b!not-for-mail From: "charlie cs" Newsgroups: comp.databases.oracle.server Subject: How many people here rebuid index regularly? Lines: 26 X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2900.3138 X-RFC2646: Format=Flowed; Original X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 Message-ID: Date: Fri, 05 Oct 2007 02:10:00 GMT NNTP-Posting-Host: 71.242.83.9 X-Complaints-To: abuse@verizon.net X-Trace: trndny09 1191550200 71.242.83.9 (Thu, 04 Oct 2007 22:10:00 EDT) NNTP-Posting-Date: Thu, 04 Oct 2007 22:10:00 EDT Xref: usenetserver.com comp.databases.oracle.server:435943 X-Received-Date: Thu, 04 Oct 2007 22:10:01 EDT (text.usenetserver.com) We are on 9i Oracle. Search on the internet, some expert say "In the overwhelming majority of cases, indexes are extremely well self-maintained and index rebuilds are NOT required, ever." Tom Kytes in his website says "The time lag between index rebuilds should be approximately FOREVER. Tell me -- why why why WHY are you rebuilding them on a schedule? What is the scientific basis in reality that is driving you to do this???? " And some other site says: "First rule of thumb is if the index has height greater than four, rebuild the index. For most indexes, the height of the index will be quite low, i.e. one or two. I have seen an index on a 3 million-row table that had height three. An index with height greater than four may need to be rebuilt as this might indicate a skewed tree structure. " Which one is right? Thanks for your comments Thanks