However, it is not at all difficult to get a high BHR with Connor's script (...if one *must* see those 'five 9s'...) at http://www.oracledba.co.uk/. Click on Tuning and the on 'Custom Hit Ratio'. While there, browse the site for some really useful things than "fixing" the BHR.
- Kirti -----Original Message----- Sent: Wednesday, October 09, 2002 9:19 PM To: Multiple recipients of list ORACLE-L ...and a high cache hit ratio (>99%) is usually an indication of a serious problem as well. Cary Millsap Hotsos Enterprises, Ltd. http://www.hotsos.com Upcoming events: - Hotsos Clinic, Oct 15-17 Dallas, Dec 9-11 Honolulu - 2003 Hotsos Symposium on OracleR System Performance, Feb 9-12 Dallas - Jonathan Lewis' Optimising Oracle, Nov 19-21 Dallas -----Original Message----- WILLIAMS Sent: Wednesday, October 09, 2002 5:04 PM To: Multiple recipients of list ORACLE-L Seema 1. How low is too low? Basically, different applications will tend to have different BHR values (Buffer Hit Ratio). 2. BHR varies over time, and will depend a lot on the lengths of time you sample it, and what type of processing was running. 3. A low BHR can lead you to a problem. Other indicators like waits can also lead you to the same problems. But the point is that you need to investigate what the problem actually is, rather than just increase the buffer cache size. 4. Changing the db_block_buffer size may increase the BHR. Sometimes it doesn't affect the BHR at all. 5. Get a copy of the book Oracle Performance Tuning 101 and you will learn more about Oracle tuning and why you don't just want to focus on the BHR and increasing the buffer cache size. Dennis Williams DBA Lifetouch, Inc. [EMAIL PROTECTED] -----Original Message----- Sent: Wednesday, October 09, 2002 4:14 PM To: Multiple recipients of list ORACLE-L Hi One of my database Cache Hit Ratio is low.I adjusted db_block_buffer and I have noticed after week again cache hit ratio became low. Can u please suggest what other things I can do to fix this problem? Thx -Seema _________________________________________________________________ Chat with friends online, try MSN Messenger: http://messenger.msn.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Seema Singh 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: 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: Cary Millsap 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: Deshpande, Kirti 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).
