I believe it refers to the number of records(rows) allowed by oracle in a block as deduced from the 'minimise records per block' clause.
Primary designed for bitmap index optimization but Jonathan shows a nifty little use for it in his book for handling disparate size rows. The bug(s) I think he is referring to is that the value stored can be out by 1 when subsequently used for a move operation. And I think there was another one where the value can be lost because the column in TAB$ (spare1 ? spare3? ) is used for multiple purposes. Of course, all of that might be just drivel... :-) Cheers Connor --- [EMAIL PROTECTED] wrote: > Jonathan, > > What is the 'Haken' factor? > > Jared > > > > > > > "Jonathan Lewis" <[EMAIL PROTECTED]> > Sent by: [EMAIL PROTECTED] > 03/24/2003 02:24 PM > Please respond to ORACLE-L > > > To: Multiple recipients of list ORACLE-L > <[EMAIL PROTECTED]> > cc: > Subject: Re: Reorganizing tables > > > > This may have been mentioned already, but a > table re-org can be a positive threat to > performance. > > If your primary tables have (for example) a > three-stage > life: > initial row size is small > row grows after a couple of weeks > row reaches full size after another 4 weeks, > then what value are you going to use for your > PCTFREE when you rebuild ? > > If you set it to zero to avoid wasting space > for the vast percentage of rows that are full > size then many incomplete rows will end up > migrating. > > If you set it to match the growth requirement > of the newest rows, then you leave lots of > empty space in the blocks that hold only old > rows. > > (The optimum storage answer is to set the > Hakan factor before moving the table - but > that's not a trivial exercise because of a bug > whose number I can't remember). > > > Regards > > Jonathan Lewis > http://www.jlcomp.demon.co.uk > > For one-day tutorials: > (see http://www.jlcomp.demon.co.uk/tutorial.html ) > > ____UK_______April 8th > ____UK_______April 22nd > ____Denmark May 21-23rd > ____USA_(FL)_May 2nd > > Next dates for the 3-day seminar: > (see http://www.jlcomp.demon.co.uk/seminar.html ) > ____UK_(Manchester)_May > ____Estonia___June (provisional) > ____USA_(CA, TX)_August > > The Co-operative Oracle Users' FAQ > http://www.jlcomp.demon.co.uk/faq/ind_faq.html > > > ----- Original Message ----- > To: "Multiple recipients of list ORACLE-L" > <[EMAIL PROTECTED]> > Sent: 24 March 2003 20:53 > > > > Thanks Jared, Rachel, Tom, Dick, Prakash, Ron > > > > Excellent points. Very much appreciated. > Unfortunately at this point > people > > are asking "but have you tested it?". So I need to > construct some > type of > > test that will demonstrate how much effect a reorg > will have. After > I've > > answered that question, then I can move on to some > of the other > issues that > > you mention. I have joked that if the results are > strongly positive, > they > > won't see me much after that because I'll be > touring the world > selling my > > performance solution that never occurred to anyone > else. > > Our test system is cloned from an RMAN backup > of production so > the tables > > should be close to production. I'm thinking of > creating a new table > and > > copying the contents of a production table into it > and then tracing > > full-table scans and comparing the results. > > > > Jared - is there a way to estimate block-level > fragmentation? > Comparing the > > average row length with the number of blocks used? > > > > Dennis Williams > > DBA, 40%OCP, 100% DBA > > Lifetouch, Inc. > > [EMAIL PROTECTED] > > > > -- > Please see the official ORACLE-L FAQ: > http://www.orafaq.net > -- > Author: Jonathan Lewis > 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.net > -- > Author: > 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). > ===== Connor McDonald web: http://www.oracledba.co.uk web: http://www.oaktable.net email: [EMAIL PROTECTED] "GIVE a man a fish and he will eat for a day. But TEACH him how to fish, and...he will sit in a boat and drink beer all day" __________________________________________________ Do You Yahoo!? Everything you'll ever need on one web page from News and Sport to Email and Music Charts http://uk.my.yahoo.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: =?iso-8859-1?q?Connor=20McDonald?= 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).
