Re: Execution time in SHARED SERVER vs. DEDICATED SERVER (RAC 10gR2)

From: Yong Huang <>
Date: Fri, 9 May 2008 09:14:47 -0700 (PDT)
Message-ID: <>

> In dedicated (where the statement(s) are slow) there are lots of wait
> events "fb contention".
> What can I do about that?
> Regards
> Martin

If dedicated config has FB contention while the shared server config has none or little, it probably has to do with the Oracle PID of the process (v$, not spid). That's something I never thought of! I think we can do an experiment to verify. And to make the shared server behave the same as dedicated, we can try event 10258 to let shared servers round robin (see "Force session to migrate to a new shared server" at

Your tablespace is ASSM? If my hypothesis correct, I think space allocation using non-ASSM would still show the same difference between dedicated and shared config if you have multiple freelists for the table you insert into (just no FB contention, maybe HW instead).

Yong Huang

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Received on Fri May 09 2008 - 11:14:47 CDT

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