Re: Buffer cache hits %
From: dreamer <1dreamer_at_home.com>
Date: Fri, 16 Jul 1999 13:02:48 GMT
Message-ID: <Y3Gj3.20190$UK2.14350_at_news.rdc1.md.home.com>
David Reamer
Sr. Oracle DBA
Technology Planning & Management Corporation
10306 Eaton Place, Suite 120
Fairfax, VA 22030
Tele: 703.383.7530
e-mail: dreamer_at_tpmc.com
Date: Fri, 16 Jul 1999 13:02:48 GMT
Message-ID: <Y3Gj3.20190$UK2.14350_at_news.rdc1.md.home.com>
DB_BLOCK_BUFFERS controls the amount of memory allocated for
the data cache. Under normal circumstances this ratio should be greater
than or equal to 95%. Typically the DB_BLOCK_BUFFERS size is 20-50% the
size of the SGA.
One difficulty in your configuration comes from running
multiple instances. Each instance will require its own
SGA. This tends to quickly eat away your physical RAM.
There are many many ways to tune your system for improved
performance. To detail each method now would be a feat. I have
creeated a Java applet that checks some of the high level performance tuning
parameters. If you would like, I could send you the source
code.
David Reamer
Sr. Oracle DBA
Technology Planning & Management Corporation
10306 Eaton Place, Suite 120
Fairfax, VA 22030
Tele: 703.383.7530
e-mail: dreamer_at_tpmc.com
Kevin Gillins <kevin_gillins_at_compuserve.com>
wrote in message news:O41ialrz#GA.309_at_nih2naae.prod2.compuserve.com...
Received on Fri Jul 16 1999 - 15:02:48 CESTI have a question about the buffer cache hits ratio we are experiencing.We are on 7.3.3.5 database using 10.7 oracle apps most all products. Apx 100+ users.The database size is apx 40 gig. We are on HP 4 processors with 2.5 gig memory.There are 2 instances both the same size (prod and test). The shared pool is setat 250,000,000 running 6 db writers. The production instance is on EMC disks.My main question is the buffer cache hit% is sitting at 90% in general. Is this good, bad orreal bad. I want to get a feel. I have tried increasing the shared pool and db_block_buffers.What other settings if any would improve this statistic. What stats could I check to seewhat contributes to the 10% miss?Your suggestions and answers are appreciated.
--
Kevin Gillins
Management Information Consulting
Boston Office
978-887-3300