I concur with Dennis. I too came off a Oracle Ed Tuning class last week and had a good instructor (who btw used John Hibbard's excellent presentation on Redo/RBS _as_well_as Cary's 'Why a 99.9% BHR is not Ok'). Maybe, just maybe, we will get there (i.e. a Non-BHR world!)
John Kanagaraj Oracle Applications DBA DBSoft Inc (W): 408-970-7002 Disappointments are inevitable in Life, but discouragement is optional. You decide! ** The opinions and statements above are entirely my own and not those of my employer or clients ** > -----Original Message----- > From: DENNIS WILLIAMS [mailto:[EMAIL PROTECTED]] > Sent: Saturday, October 05, 2002 3:13 PM > To: Multiple recipients of list ORACLE-L > Subject: Oracle Performance Tuning Class - update > > > List > I spent last week at an official Oracle Education Oracle9i > Performance > Tuning Class, and here is some of the non-technical stuff I learned. > - Oracle is teaching the wait interface more and more. In > fact, they are > updating the curriculum next month to emphasize the wait > interface even more > (lucky me). > - Just how the wait interface is emphasized may depend > quite a bit on the > instructor, despite what the materials say. My observation is that our > opinions are based on what we have experienced and our > interpretations of > those experiences. So we will probably still have some > instructors that will > still feel that the wait interface is a passing fad and if > you really want > to straighten out a database, you need to get in there and > improve the BHR > (Buffer Hit Ratio). > - My instructor was John Hibbard. He is excellent, and I > would highly > recommend him. He went well beyond the class materials to > providing papers > he has researched and presented himself, as well as other > sources, including > papers from Cary Milsap and Jonathan Gennick who participate > on this list. > When you get through his class, you really feel you have been > taken to a > whole new level of Oracle knowledge. He is also heavily involved in > selecting and preparing the official Oracle training materials for the > courses he teaches. Besides Performance Tuning, he teaches > several other > Oracle classes. Most of the people in my class happened to be more > experienced with Oracle, and John did a good job of answering advanced > questions with some depth, but not leaving the newbies in the dust. > - A funny observation on buffer hit ratio vs. wait > interface. The last > day of class is an opportunity to take a really screwed-up > database and > apply a little of what you have learned. The first scenario is titled > "Buffer Cache". So you run the workload assignment and > STATSPACK and look at > the BHR and say "wow, that is bad", increase the buffer pool, > and rerun the > workload and STATSPACK. The BHR hasn't changed much, so the > tendency is to > dumbly bump the buffer pool even more and go again. Then you > look down at > the top 5 waits section just below on the first page of the > STATSPACK report > and see that the big wait item is "Scattered Read". Then you > go "dope slap" > and realize this schema is missing some critical indexes and > table scanning > it's little heart out. I just found it ironic that some > people have reported > that some of the Oracle instructors emphasize the BHR too > much when the > first Workshop Scenario has a great example of why focusing > on BHR can't > solve many problems. But again, we have experience vs. > interpretation of > experience. A real died-in-the wool BHR fanatic would > probably claim that > BHR had solved the problem because the first indication that > something was > wrong was spotting the bad BHR, which led to other investigations. > > > Dennis Williams > DBA > Lifetouch, Inc. > [EMAIL PROTECTED] > > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.com > -- > Author: DENNIS WILLIAMS > 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: John Kanagaraj 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).