Return-Path: Delivered-To: 2-oracle-l@orafaq.com Received: (qmail 24346 invoked from network); 11 Dec 2007 12:36:27 -0600 Received: from freelists-180.iquest.net (HELO turing.freelists.org) (206.53.239.180) by static-ip-69-64-49-119.inaddr.intergenia.de with SMTP; 11 Dec 2007 12:36:26 -0600 Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id E84797D7AE5; Tue, 11 Dec 2007 13:36:26 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing.freelists.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 13220-01; Tue, 11 Dec 2007 13:36:26 -0500 (EST) Received: from turing (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 577B47D7835; Tue, 11 Dec 2007 13:36:26 -0500 (EST) Received: with ECARTIS (v1.0.0; list oracle-l); Tue, 11 Dec 2007 12:49:30 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id E394C7D7718 for ; Tue, 11 Dec 2007 12:49:29 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing.freelists.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 04177-02-3 for ; Tue, 11 Dec 2007 12:49:29 -0500 (EST) Received: from smtp1.aina.net (smtp1.aina.net [81.16.64.154]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 73F927D7703 for ; Tue, 11 Dec 2007 12:49:29 -0500 (EST) Received: from webmail.ainaratkaisu.fi (mail.ainaratkaisu.fi [81.16.64.150]) by smtp1.aina.net (Postfix) with ESMTP id 9A7AFAB03DC; Tue, 11 Dec 2007 19:49:20 +0200 (EET) Received: from 62.142.244.186 (SquirrelMail authenticated user riku.rasanen@kantamestarit.fi) by webmail.ainaratkaisu.fi with HTTP; Tue, 11 Dec 2007 19:49:20 +0200 (EET) Message-ID: <1509.62.142.244.186.1197395360.squirrel@webmail.ainaratkaisu.fi> In-Reply-To: <4ef2fbf50712101621r1c98c50ft1a542af3ec39d105@mail.gmail.com> References: <578806DDE66A3A45916740EB73C6982AB42BB5D391@M1EXCHANGE01.mmi.local> <04DDF147ED3A0D42B48A48A18D574C450999D439@NT15.oneneck.corp> <2509.62.142.244.186.1197317491.squirrel@webmail.ainaratkaisu.fi> <4ef2fbf50712101621r1c98c50ft1a542af3ec39d105@mail.gmail.com> Date: Tue, 11 Dec 2007 19:49:20 +0200 (EET) Subject: Re: Operations that perform multiblock I/O and cluster factor From: Riku =?iso-8859-1?Q?R=E4s=E4nen?= To: alberto.dellera@gmail.com Cc: oracle-l@freelists.org User-Agent: SquirrelMail/1.4.8 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 X-smtp1.aina.net-MailScanner-Information: Please contact the ISP for more information X-smtp1.aina.net-MailScanner: Found to be clean X-smtp1.aina.net-MailScanner-From: riku.rasanen@kantamestarit.fi X-archive-position: 3843 X-ecartis-version: Ecartis v1.0.0 Sender: oracle-l-bounce@freelists.org Errors-to: oracle-l-bounce@freelists.org X-original-sender: riku.rasanen@kantamestarit.fi Precedence: normal Reply-to: riku.rasanen@kantamestarit.fi List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: oracle-l X-List-ID: oracle-l List-subscribe: List-owner: List-post: List-archive: X-list: oracle-l X-Virus-Scanned: Debian amavisd-new at localhost.localdomain I had deleted the tracefile, but I did have a script to reproduce the results. This trace was so unusual, so that I made notes about it, in case if I happened to run into this again. I re-run it today and the results match to those I saw earlier. This is Oracle 9.2.0.4 on Linux, table (~80MB) placed in small (4MB) recycle pool, index should fit in memory in default pool. The test query is run from inside a anonymous PL/SQL block using bulk fetch. This is a snippet from the raw trace. To me the interesting thing is the p3-parameter, as DB_FILE_MULTIBLOCK_READ_COUNT is actually set to 16 and normal FTS reads 16 blocks at a time. The "db file scattered read"s are all for the table, the index should be cached. PARSING IN CURSOR #6 len=74 dep=1 uid=0 oct=3 lid=0 tim=1169333298070551 hv=668808299 ad='5ba07778' SELECT /*+INDEX (c idx_clf_scattered) */ c.* FROM DEMO.clusfac_demo c END OF STMT PARSE #6:c=1000,e=1510,p=0,cr=0,cu=0,mis=1,r=0,dep=1,og=4,tim=1169333298070527 BINDS #6: EXEC #6:c=0,e=137,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=4,tim=1169333298070916 WAIT #6: nam='db file scattered read' ela= 2659 p1=6 p2=1034 p3=40 WAIT #6: nam='db file scattered read' ela= 2241 p1=6 p2=1074 p3=40 WAIT #6: nam='db file scattered read' ela= 2254 p1=6 p2=1114 p3=40 WAIT #6: nam='db file parallel read' ela= 1598 p1=1 p2=40 p3=40 WAIT #6: nam='db file scattered read' ela= 2280 p1=6 p2=1322 p3=40 WAIT #6: nam='db file scattered read' ela= 2281 p1=6 p2=1362 p3=40 WAIT #6: nam='db file scattered read' ela= 2281 p1=6 p2=1402 p3=40 WAIT #6: nam='db file scattered read' ela= 2253 p1=6 p2=1442 p3=40 WAIT #6: nam='db file scattered read' ela= 2258 p1=6 p2=1482 p3=40 WAIT #6: nam='db file scattered read' ela= 2257 p1=6 p2=1522 p3=40 WAIT #6: nam='db file scattered read' ela= 2246 p1=6 p2=1562 p3=40 WAIT #6: nam='db file scattered read' ela= 2257 p1=6 p2=1602 p3=40 WAIT #6: nam='db file scattered read' ela= 2246 p1=6 p2=1642 p3=40 WAIT #6: nam='db file scattered read' ela= 2248 p1=6 p2=1682 p3=40 WAIT #6: nam='db file scattered read' ela= 2247 p1=6 p2=1722 p3=40 WAIT #6: nam='db file scattered read' ela= 2278 p1=6 p2=1762 p3=40 WAIT #6: nam='db file scattered read' ela= 2275 p1=6 p2=1802 p3=40 WAIT #6: nam='db file scattered read' ela= 2258 p1=6 p2=1842 p3=40 WAIT #6: nam='db file scattered read' ela= 2225 p1=6 p2=1882 p3=40 WAIT #6: nam='db file scattered read' ela= 2217 p1=6 p2=1922 p3=40 WAIT #6: nam='db file scattered read' ela= 2230 p1=6 p2=1962 p3=40 WAIT #6: nam='db file scattered read' ela= 2234 p1=6 p2=2002 p3=40 WAIT #6: nam='db file scattered read' ela= 2212 p1=6 p2=2042 p3=40 WAIT #6: nam='db file scattered read' ela= 2229 p1=6 p2=2082 p3=40 -- Riku Räsänen Kantamestarit OY www.kantamestarit.fi -- http://www.freelists.org/webpage/oracle-l