Return-Path: Received: from newsfeed.cts.com (newsfeed.cts.com [209.68.248.164]) by naude.co.za (8.11.2/8.11.2) with SMTP id g5L3DGn12552 for ; Thu, 20 Jun 2002 23:13:16 -0400 Received: from fatcity.UUCP (uucp@localhost) by newsfeed.cts.com (8.9.3/8.9.3) with UUCP id MAA19141; Thu, 20 Jun 2002 12:13:04 -0700 (PDT) Received: by fatcity.com (26-Feb-2001/v1.0g-b71/bab) via UUCP id 0048352D; Thu, 20 Jun 2002 11:53:45 -0800 Message-ID: Date: Thu, 20 Jun 2002 11:53:45 -0800 To: Multiple recipients of list ORACLE-L X-Comment: Oracle RDBMS Community Forum X-Sender: Stephane Faroult Sender: root@fatcity.com Reply-To: ORACLE-L@fatcity.com Errors-To: ML-ERRORS@fatcity.com From: Stephane Faroult Subject: Re: Query Tuning Organization: Fat City Network Services, San Diego, California X-ListServer: v1.0g, build 71; ListGuru (c) 1996-2001 Bruce A. Bergman Precedence: bulk Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 X-MIME-Autoconverted: from 8bit to quoted-printable by newsfeed.cts.com id MAA19141 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by naude.co.za id g5L3DGn12552 Rajesh.Rao@jpmchase.com wrote: > > Hello Folks, > > Given an Oracle 7.3.4 database, how would you tune a query as under, other > than suggesting a migration to a higher version. This query is currently > performing a lot of I/O, obviously doing a full tablescan on CAMPMAIN. > > SELECT CAMPNAME,ASGNMTTYPE,CAMPRTGNUM, LTRIM(RTRIM(CAMPTYPE)) > FROM CAMPMAIN > WHERE LTRIM(RTRIM(CAMPNAME)) = :b1 > AND (LOAD_FAILED_FLG = 'N' OR LOAD_FAILED_FLG = '' OR LOAD_FAILED_FLG IS > NULL ); > > This query runs in a PL/SQL loop. For now, my suggestion was to create a > temporary table with all the fields and a fully trimmed CAMPNAME field > outside the loop, create an index on this table, and then use this > temporary table inside the loop. Any better suggestions? > > Regards > Raj > 1) What the $%ща#? is this LTRIM(RTRIM()) doing? CAMPNAME and CAMPTYPE are CHAR instead of VARCHAR2 ? You are right to want to clean-up your data. 2) Queries inside loop are rarely useful. Try to rethink in terms of INSERT ... SELECT if you are inserting, or UPDATE SET (..., ... ) = (SELECT ....) if updating. In-line views can help too. Ah, and if you are using your SELECT to use the result into another SELECT, there's something named a join. -- Regards, Stephane Faroult Oriole Software -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Stephane Faroult INET: sfaroult@oriole.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru@fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).