Re: Oracle slowed down

From: <stevedhoward_at_gmail.com>
Date: 21 Apr 2006 08:33:05 -0700
Message-ID: <1145633585.224964.56360@u72g2000cwu.googlegroups.com>

I think I understand where Bob is coming from. I think he is saying that *after* you have tuned the application, you could look to get more of the remaining required buffers from Oracle memory than from disk
(whatever that is nowadays, with OS cache, SAN cache, etc.). One
logical way (once again, after you have removed the low hanging SQL fruit) is to "encourage" Oracle to get more blocks that are needed from memory rather than "disk".

My issue is that nowdays you don't know exactly where your phyiscal data is coming from because of all the different caches, so a physical read may not be much more expensive than a pointer read in memory.

Also, if you "tune" the buffer cache too much, you may start changing execution plans when Oracle determines if it has a different amount
(either larger or smaller) with which to work.

Regards,

Steve Received on Fri Apr 21 2006 - 10:33:05 CDT