Hi Jared I have reset to previous value and restarted the database anyway. Since I have 8G Memory and I may set SGA more than 3G. Actually I did at our AIX SP that set SGA total up to 5G of 8G memory.
Anyway I found a solution on metalink ( Note 115753.1 and 1028623.6. ) to set SGA to higher. You may be interest to read it. You are right it is best to find a root cause of poor performance. The reason I want to increases db buffer is our customer complain slow on our database and Statpack report suggest to increase it as well Thanks Mitchell ----- Original Message ----- To: <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> Sent: Friday, August 15, 2003 10:42 AM > Was a low cache hit ratio the only 'problem'? > > Were jobs taking longer than normal? > > Were users complaining of a slow system? > > Did your average response time shoot up dramatically? > > I'm afraid you may have succumbed to the dreaded disease, > CTD, or Compulsive Tuning Disorder. > > This is the urge to tweak database parameters due to some > arbitrary threshold. even though everything seems to be > working fine. > > It isn't your fault, as a number of publications in the > past, including Oracle's, have taught that having a block > cache hit ratio, or BCHR, lower than 90 or 95% meant that > your system was performing poorly. > > The first thing to do is set your db_block_buffers size > back to a value that allows you to start the database. > > Then head on over to http://www.hotsos.com and register > for the site. Click on 'Knowledge On-Line' at the top > of the page, and get the paper "Why 99% Database Buffer > Cache Hit Ratio is NOT Ok". > > There are other useful papers there as well, and indeed > many other sites where you can find useful information > about BCHR. This will get you started. > > Of course, someone (Connor McDonald I think) wrote a nice > utility that will increase your BCHR for you, but I don't > think you want to use it in production. :) It's chief > purpose is to underscore the futility of trying to tune > via the block cache hit ratio. > > HTH > > Jared > > > > > On Thu, 2003-08-14 at 16:19, Mitchell wrote: > > Hi DBAs > > > > We have Sun Sparc system (Sun Fire 880) with 8G memeory. We has setting > > /etc/system to the max and data buffer catch 1000m and total SGA 1745MB on > > our . Oracle 8.1.7.3.0 Server. Since Dat Buffer Cache hit ration > > lower then 50% for last a few days, So We decide to increase another 400MB > > to DB buffer. We faile to restart instance then, reside to 1200M, still > > failed. I have no clue at all for why. (I have checked the Metalink, no > > solution but redece SGA size). Anybody has any idea? > > > > Thanks in advance. > > > > Mitchell > > > > > > > > -- > > Please see the official ORACLE-L FAQ: http://www.orafaq.net > > -- > > Author: Mitchell > > 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: Mitchell 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).
