From carmichr@hotmail.com Wed, 09 May 2001 16:18:00 -0700 From: "Rachel Carmichael" Date: Wed, 09 May 2001 16:18:00 -0700 Subject: Re: consistency in cost? Message-ID: MIME-Version: 1.0 Content-Type: text/plain woo hoo! Bambi's back and we've got her! :) welcome home, you've been missed >From: "Bambi Bellows" >Reply-To: ORACLE-L@fatcity.com >To: Multiple recipients of list ORACLE-L >Subject: Re: consistency in cost? >Date: Wed, 09 May 2001 14:31:01 -0800 > >Tim -- > >Oh, sure, bring LOGIC into it. Truth of the matter is that Oracle is >trying to phase out the last vestiges of v5, and that's never EVER going to >happen. Logic be dammed! Mwahahahaha! > >Bambi. > >------Original Message----- >Date: Wed, 09 May 2001 05:01:06 -0800 >To: Multiple recipients of list ORACLE-L > > > > Interesting...CHOOSE means Oracle will decide whether to use RULE or >COST. But a CHOOSE hint will force use of COST. Kind of diminishes the >meaning of CHOOSE, doesn't it? Seems like a pointless hint... > > > > >>> rabbit@emirates.net.ae 05/08/01 11:45PM >>> > > If the system is Rule based and you code Hints, the CBO will be > > automatically invoked > > Sam > > > > > > ----- Original Message ----- > > To: "Multiple recipients of list ORACLE-L" > > Sent: Tuesday, May 08, 2001 10:12 PM > > > > > > > Forgive my ignorance but I thought hints were only for cost based > > optimizer. > > > > > > > > > Have you checked in case anybody has changed any parameters while the > > system > > > is running as I know that changing the hash_area_size can change the > > > execution plan?. Are you using parallelism as if a table had to be > > > recreated for any reason and its degree changed it might do a FTS? > > > > > > Cheers > > > > > > Iain Nicoll > > > > > > > > > -----Original Message----- > > > Sent: 08 May 2001 17:31 > > > To: Multiple recipients of list ORACLE-L > > > > > > > > > Jared, > > > The only difference is about a weeks worth of extra data. Well, the > > hardware > > > is also different (Ultra450 vs. Ultra 5000. Also 1 vs 4 CPU). But > > > regardless, shouldn't init.ora optimizer_mode=choose be identical to > > > optimizer_mode=rule with hint=choose? If I have the time, I'll try to >set > > up > > > a couple of systems and examine by moving stats and taking some 10053 > > dumps. > > > (one of the ones giving me a problem is in production so I have >limited > > play > > > time there). > > > > > > Henry > > > > > > -----Original Message----- > > > Sent: Tuesday, May 08, 2001 12:56 AM > > > To: ORACLE-L@fatcity.com; Henry Poras > > > > > > > > > > > > Henry, > > > > > > You say 'nearly identical'. > > > > > > What are the differences? > > > > > > Are the 2 databases on the same platform? > > > > > > If not, what are the differences, hardware and OS? > > > > > > Jared > > > > > > > > > On Monday 07 May 2001 21:55, Henry Poras wrote: > > > > I am working with an 8.1.6 database on Solaris 2.6 and I am >wondering if > > > > there is any consistency in the optimizer. We have two nearly >identical > > > > databases (one a clone from two weeks ago). A five table join has >nearly > > > > the identical execution plan on the two databases. The difference is >in > > > the > > > > access method of the fourth table in the join; in one case it is > > accessed > > > > by a FTS and in the other, by Index. This difference has a large >effect > > on > > > > performance. Statistics are nearly identical for this table in both > > > > databases (I looked at dba_tables, dba_indexes, dba_col_tables). >Also, > > the > > > > init.ora is the same. When I changed the optimizer_mode to rule and > > added > > > a > > > > 'choose' hint to the query, the execution plan was different again. >I > > will > > > > look into this a bit further and post my results. Just wondering >about > > > > other's experiences. Thanks. > > > > > > > > Henry > > > -- > > > Please see the official ORACLE-L FAQ: TARGET="_new">http://www.orafaq.com > > > -- > > > Author: Henry Poras > > > INET: Henry.Poras@ctp.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). > > > -- > > > Please see the official ORACLE-L FAQ: TARGET="_new">http://www.orafaq.com > > > -- > > > Author: Nicoll, Iain (Calanais) > > > INET: iain.nicoll@calanais.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). > > > > -- > > Please see the official ORACLE-L FAQ: TARGET="_new">http://www.orafaq.com > > -- > > Author: Sam Roberts > > INET: rabbit@emirates.net.ae > > > > 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). > > -- > > Please see the official ORACLE-L FAQ: TARGET="_new">http://www.orafaq.com > > -- > > Author: Tim Sawmiller > > INET: sawmillert@state.mi.us > > > > 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). > > > >-- > >_______________________________________________ >Get your free email from http://www.mail.com > >-- >Please see the official ORACLE-L FAQ: http://www.orafaq.com >-- >Author: Bambi Bellows > INET: ultrageek@techie.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). _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Rachel Carmichael INET: carmichr@hotmail.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).