Vadim, Apologies, I answered the question you didn't ask - viz why does it take so long, rather than the 'what are the CR gets'.
Your second suggestion is the correct one. It seems unreasonable, but when you do the "select for update", Oracle seems to go through a load of read- consistency work for the block to roll back the changes made by other transactions. The excess CR gets are accesses to the UNDO blocks need to build the CR image. Strangely, if you just slam in the 'update', rather than 'select for update' this phenomenon does not occur. Regards Jonathan Lewis http://www.jlcomp.demon.co.uk Now available One-day tutorials: Cost Based Optimisation Trouble-shooting and Tuning Indexing Strategies (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 ____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: 13 March 2003 18:54 > Thank you, Jonathan, > > I'll continue looking for my options to cool down the hot spots. Not sure if > I can go for partitioning since Oracle charges $$$. > > Is it correct that oracle counts looking through the chain > for the correct copy as many CR? Or the reason for these extra CR is access > to undo segments in attemt to reconstruct CR block aged out from cache? > > Thanks > Vadim > > -- 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).
