If anyone's after a nice high hit ratio, you can download the source for procedure "choose_hit_ratio" from my site...Some examples:
SQL> exec choose_a_hit_ratio(90); Current ratio is: 86.24731 Another 79053 consistent gets needed... Current ratio is: 90.5702 PL/SQL procedure successfully completed. SQL> exec choose_a_hit_ratio(98,true); Current ratio is: 90.5709 Another 1141299 consistent gets needed... Magic for consultants like myself.. "You want a hit ratio of 98%... No problem" :-) --- "Deshpande, Kirti" <[EMAIL PROTECTED]> wrote: > Not quite !! 99.999% or 'the five nines' sounds much > better ;-) > > With 64-bit computing we can address SGA sizes in > the order of few TBs (if > not PBs), why worry about disk I/Os except for two > occasions ;-)) Then the > 'five nines' can be 'nine nines'. Wow!! That sounds > even better.. much much > better ;-))) > > > - Kirti > > -----Original Message----- > Sent: Wednesday, March 20, 2002 5:48 AM > To: Multiple recipients of list ORACLE-L > > > Cary Milsap from hotsos has much data to confirm an > approximate 1:100 ratio > between LIO time and PIO time. > > Can we therefore conclude, that the buffer cache hit > ratio should be 99%? > :-) > > Rgds, Bj�rn. > On Wednesday 20 March 2002 10:48, Connor McDonald > wrote: > > Some rudimentary testing on a laptop here (500Mhz, > > 512M RAM, typical single disk) > > > > a) visiting a single block via 4,000,000 logical > IO's > > got me approx 35000 gets/sec > > > > b) repeated full table scans similar system got me > > approx 350 phys reads/sec > > > > After this extensive, thorough and exhaustive > > exercise, I can definitely say that memory access > > versus disk access (as it pertains to Oracle) is > 100 > > times faster on this machine in single user mode > > > > I think we can generalise this to be the rule for > all > > servers under all conditions :-) > > > > Connor > > > > > -- > Please see the official ORACLE-L FAQ: > http://www.orafaq.com > -- > Author: Deshpande, Kirti > 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). ===== Connor McDonald http://www.oracledba.co.uk (mirrored at http://www.oradba.freeserve.co.uk) "Some days you're the pigeon, some days you're the statue" __________________________________________________ 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.com -- Author: =?iso-8859-1?q?Connor=20McDonald?= 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).
