Thanks Jhonatan and every one I'm in 9.2, and as in a previous post, and in Tom kyte's book I can use system statics, I had ask to Tom Kyte his opinion about "don't touch them". Once he giveme an answer I'll continue this post, becaues is very confusing, their usage, it seem to be a hidden parameter only used when needed. :) ----- Original Message ----- From: "Jonathan Lewis" <jonathan@xxxxxxxxxxxxxxxxxx> To: <oracle-l@xxxxxxxxxxxxx> Sent: Thursday, March 25, 2004 12:51 PM Subject: Re: how to set optimizer_index_cost_adj and cache parameters? > > Just in case you haven't come across it, the following > article of mine has just been published on DBAZine: > > www.dbazine.com/jlewis18.shtml > > OICA is a bit of a threat because it's often treated > as a standalone solution, when it's really part of > a strategy for getting the truth into the optimizer. > > It's also a bit of a bodge job in 8.1 anyway, because > it tries to fix two issues simultaneously (caching and > relative read speeds). It is also easy to set it to an > inappropriate value because of the impact that bad > SQL can have on your attempts to work out a > reasonable value. > > Just to add to the confusion - whatever you do in > 8.1 should be reconsidered for 9.2 anyway, where > system statistics can be used to set relative I/O speeds > and OICA can be used as an indicator of caching benefits > on tables. > > Regards > > Jonathan Lewis > http://www.jlcomp.demon.co.uk > > The Co-operative Oracle Users' FAQ > http://www.jlcomp.demon.co.uk/faq/ind_faq.html > > April 2004 Iceland http://www.index.is/oracleday.php > June 2004 UK - Optimising Oracle Seminar > > > ----- Original Message ----- > From: "Juan Cachito Reyes Pacheco" <jreyes@xxxxxxxxxxxxxxxx> > To: <oracle-l@xxxxxxxxxxxxx> > Sent: Thursday, March 25, 2004 1:23 PM > Subject: how to set optimizer_index_cost_adj and cache parameters? > > > : Hi, > : > : After reading a lot about this, this is my conclusion, do you agree? > : > : the conclusion seems to be gather system statics from every distinct > process > : or group of process, and set manually this values in every one of them. > : > : If this process is by time, for example night and day, you can use alter > : system parameter, > : if this is only for ap articular process you will have to set alter > session. > : > : And set the value. > : This seems to be a hard work. > : > : regards, > : > > > ---------------------------------------------------------------- > Please see the official ORACLE-L FAQ: http://www.orafaq.com > ---------------------------------------------------------------- > To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx > put 'unsubscribe' in the subject line. > -- > Archives are at //www.freelists.org/archives/oracle-l/ > FAQ is at //www.freelists.org/help/fom-serve/cache/1.html > ----------------------------------------------------------------- ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx put 'unsubscribe' in the subject line. -- Archives are at //www.freelists.org/archives/oracle-l/ FAQ is at //www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------