Well, besides the paper you found, Jonathan Lewis has a myths section with his site: http://www.jlcomp.demon.co.uk/myths.html
Gaja also has a good "myths" article: http://www.quest-pipelines.com/newsletter-v3/0302_F.htm Rachel, weren't you doing a presentation on Oracle myths (or did you just put that in DBA 101)? Jeffery Stevenson Chief Databeast Slayer Medical Present Value, Inc. Austin, TX ----- Original Message ----- To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Monday, November 11, 2002 10:58 AM > So, there I am, on 8.1.7.2 (and .4) on HP/UX 11.0, with a process that runs > 20 minutes out of every hour of the day (despite my protests to it's > design). After it starts having problems (go figure), it becomes a priority > to speed it up. > > Thanks to a 10046 trace, we see that the query taking the most elapsed time > does FTSs on each of two very small tables (1 block and 4 blocks -- 8K > blocksize). These tables are not indexed, as per the official Oracle > recommendation. After reading the excellent Hotsos paper "When to index a > table" (THANKS, CARY!), I added an index to reduce elapsed time on this > query by 50% (150 to 75 seconds in test), proving to me that the paper is > valid. And I've only read to page four! > > OK, first I'm taught by Oracle to look at Buffer Cache Hit Ratios as a > measure of performance, then told (and thoroughly convinced) by experts that > this is bunk. Now, I found out that the 15% (or 10% or whatever, depending > on version) ratio of rows returned to total rows in determining when to use > an index in a query is garbage. > > 1) Why is this? > > 2) What other pearls of performance wisdom from Oracle Corp should I > completely disregard as false? > > I know there's an Oracle Fallacy website somewhere... > > It just looks bad on me, our department, and Oracle when, once again, > something I've been preaching to our developers as gospel turns out to be > completely false. > > Maybe I'm grumpy because it's snowing on my leaves right now... <sigh> > > > Rich > > > Rich Jesse System/Database Administrator > [EMAIL PROTECTED] Quad/Tech International, Sussex, WI USA > > Disclaimer: I only said the Packers would be 12-4 this year -- I never said > that they couldn't do better! WOO-HOO! :) > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.com > -- > Author: Jesse, Rich > INET: [EMAIL PROTECTED] > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > San Diego, California -- Mailing list and web hosting services > --------------------------------------------------------------------- > To REMOVE yourself from this mailing list, send an E-Mail message > to: [EMAIL PROTECTED] (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). > > -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Jeffery Stevenson INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (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).
