These numbers are all virtually zero. There have been virtually no sleeps since your instance was last restarted.
Now, what this kind of query DOESN'T show is whether any of those sleeps consumed dozens of seconds of some user's response time. Having an infinitesimally small number of sleeps per get is, I guess, better than having a large number of sleeps per get. But it's impossible from just this ratio to determine whether you have a performance problem or not. (This type of flaw is inherent in virtually *any* ratio query.) <advice>If you're experiencing system performance problems, analyze the response times of the problem sessions. See www.hotsos.com/dnloads/1/10046a for one way of doing it.</advice> <advice type="corollary">DON'T start at the inside of your database looking for ratios that may or may not indicate a response time problem. This way takes longer, it's less reliable, and it wastes cash.</advice> Cary Millsap Hotsos Enterprises, Ltd. http://www.hotsos.com Upcoming events: - Hotsos Clinic, Jul 9-11 New York City - Hotsos Clinic, Jul 23-25 Chicago - 2003 Hotsos Symposium on OracleR System Performance, Feb 9-12 Dallas -----Original Message----- Lorraine Sent: Wednesday, July 03, 2002 5:22 PM To: Multiple recipients of list ORACLE-L So this is not good: CHILD# RATIO ------- ------- 16 8.5E-06 15 .000013 14 7.5E-06 13 6.5E-06 12 8.2E-06 11 .00001 10 9.3E-06 9 9.1E-06 8 8.4E-06 7 .000012 6 9.5E-06 5 8.5E-06 4 9.8E-06 3 9.1E-06 2 8.9E-06 1 .000008 16 rows selected. Enter value for child_latch_number: 16 old 3: WHERE lo_setid <= &&child_latch_number new 3: WHERE lo_setid <= 16 old 4: AND hi_setid >= &&child_latch_number new 4: AND hi_setid >= 16 NAME -------------------- KEEP RECYCLE DEFAULT At 01:07 PM 7/3/2002 -0800, [EMAIL PROTECTED] wrote: >If you aren't experiencing performance problems, the best thing to do >is nothing. > > >From the docs ( Designing and Tuning for Performance ) > >To determine whether your system is experiencing latch contention, begin >by determining whether there is LRU latch contention for any individual >latch. > >SELECT CHILD#, SLEEPS / GETS RATIO >FROM V$LATCH_CHILDREN >WHERE NAME = 'cache buffers lru chain'; > > >The miss ratio for each LRU latch should be less than 3%. A ratio above 3% >for any particular latch is indicative of LRU latch contention and should >be addressed. >You can determine the buffer pool to which the latch is associated as >follows: > >SELECT NAME >FROM V$BUFFER_POOL >WHERE lo_setid <= child_latch_number >AND hi_setid >= child_latch_number; > >Jared > > > > > > >Hamid Alavi <[EMAIL PROTECTED]> >Sent by: [EMAIL PROTECTED] >07/03/2002 08:58 AM >Please respond to ORACLE-L > > > To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> > cc: > Subject: db_block_lru_latches > > >List, > >I have a question regarding db_block_lru_latches, I have read in some >book(can't remember) which the best number for this parameter is (number >of >CPU)*6 or db_block_buffers/50. >But these two result is diffrent,anybody have any idea what's the best >configuration for this parameter. >In my configuration it has been set to 1 as default and I have two CPU so >it >means it should be 6*2 = 12?is it right? >Thanks allot for your recommendation. > > > > > >Hamid Alavi >Office 818 737-0526 >Cell 818 402-1987 > > > > > > >======================= Confidentiality Statement ======================= >The information contained in this message and any attachments is >intended only for the use of the individual or entity to which it is >addressed, and may contain information that is PRIVILEGED, CONFIDENTIAL >and exempt from disclosure under applicable law. If you have received >this message in error, you are prohibited from copying, distributing, or >using the information. Please contact the sender immediately by return >e-mail and delete the original message from your system. >===================== End Confidentiality Statement ===================== > > >-- >Please see the official ORACLE-L FAQ: http://www.orafaq.com >-- >Author: Hamid Alavi > 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). > > > >-- >Please see the official ORACLE-L FAQ: http://www.orafaq.com >-- >Author: > 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). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Deborah Lorraine 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). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Cary Millsap 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).
