I've got it on my list of things I'd like to do (i.e. understand DBMS_STATS.GATHER_SYSTEM_STATS), but I don't see any time to do it anytime soon. :-(
It makes sense that the use of this procedure should obsolesce both OPTIMIZER_INDEX_xxxx parameters... ----- Original Message ----- To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Wednesday, April 24, 2002 2:48 PM > It's interesting that you should have heard that. > > My first interpretation of the optimizer_index_cost_adj > was that it was an estimate of the table logical I/O that > would become physical I/O (and ignore the fact that > this was allowed to go above 100%) - which brings > it into line, somewhat, with the optimizer_index_caching > in terms of 'addressing the same issue'. > > However, I decided that your interpretation was > a much nicer, more intuitive, way of appreciating > the significance of the number and deciding on > a rational setting for it. > > But I'm inclined to agree with you - even if they were > supposed to be addressing the same problem in > different ways, they do seem to be jointly and > separately (as the lawyers say) viable. > > Have you tried any experiments yet which > mix dbms_stats.system_stats figures with > the effects of these two parameters ? That > ought to be a case of when we should do one > or the other. > > Jonathan Lewis > http://www.jlcomp.demon.co.uk > > Author of: > Practical Oracle 8i: Building Efficient Databases > > Next Seminar - Australia - July/August > http://www.jlcomp.demon.co.uk/seminar.html > > Host to The Co-Operative Oracle Users' FAQ > http://www.jlcomp.demon.co.uk/faq/ind_faq.html > > > > -----Original Message----- > > At IOUG-A, I heard discussion that the OPTIMIZER_INDEX_CACHING and > OPTIMIZER_INDEX_COST_ADJ were two separate approaches developed by > different > development teams within Oracle that had the exact same purpose. So, > the > argument was advanced that setting *either* one *or* the other was > sufficient, but not *both*. Not having any access to the internal > goings-on > in Oracle ST Development, I'm sticking with the idea that these two > parameters are addressing *different* and very specific issues, so > they both > should be considered and used independently of one another... > > I have a paper on this topic at > http://www.EvDBT.com/SearchIntelligenceCBO.doc that discusses these > issues > in more depth... > > > > > > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.com > -- > Author: Jonathan Lewis > INET: [EMAIL PROTECTED] > > 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: [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: Tim Gorman INET: [EMAIL PROTECTED] 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: [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).
