I don't recall where I read this but I remember a few things about it. As you noted, the use of SESSION_CAHED_CURSORS has an impact on the UGA. If you are using MTS then that becomes part of the SGA in the shared pool (or large pool depending on your settings.) Also, attempts by the client to destroy the cursor are ignored. A beneficial effect is that upon the 3rd execution of a specific cursor (explicit or implicit) the statement's plan is cached in the UGA and subsequent executions are satisfied from that private cache. This relieves the shared pool (and its memory structures) from the burden of caching those statements, and relieves the session from serializing on the shared pool resources. The session will look at its private cache first to find SQL and go to the shared pool if it's a miss.
HTH
Tony Aponte
-----Original Message-----
From: Jesse, Rich [mailto:[EMAIL PROTECTED]]
Sent: Monday, June 24, 2002 12:34 PM
To: Multiple recipients of list ORACLE-L
Subject: SESSION_CACHED_CURSORS and shared_pool sizing.
Hi all,
Trying to deal with SHARED_POOL sizing and perf tuning for an 8.1.6.0.0 DB
that's used by 3rd party software. I can't seem to find if higher values of
SESSION_CACHED_CURSORS adversely affects the shared pool in any way.
Specifically, I'm wondering if the higher number of cached cursors can keep
objects from being flushed from the shared pool.
I believe that higher values of SESSION_CACHED_CURSORS require more mem for
the UGAs, but I'm looking for effects on the SGA.
My apologies to Steve Adams -- I haven't read that far in his "Internals"
book yet! :)
TIA!
Rich Jesse System/Database Administrator
[EMAIL PROTECTED] Quad/Tech International, Sussex, WI USA
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