This is 9205 RAC on Linux, so consider the numbers as you like. Very similar with our apps on single instance for the dispatcher CPU consumption. CPU time since process startup from ps: oracle 2461 1 0 Jul06 ? 00:01:09 ora_pmon_db2 oracle 2463 1 0 Jul06 ? 00:03:08 ora_diag_db2 oracle 2467 1 0 Jul06 ? 01:19:29 ora_lmon_db2 oracle 2469 1 0 Jul06 ? 01:47:34 ora_lmd0_db2 oracle 2471 1 0 Jul06 ? 10:48:54 ora_lms0_db2 oracle 2473 1 0 Jul06 ? 10:25:25 ora_lms1_db2 oracle 2475 1 0 Jul06 ? 00:41:58 ora_dbw0_db2 oracle 2477 1 0 Jul06 ? 02:33:29 ora_lgwr_db2 oracle 2481 1 0 Jul06 ? 00:14:09 ora_smon_db2 oracle 2483 1 0 Jul06 ? 00:00:00 ora_reco_db2 oracle 2485 1 0 Jul06 ? 00:13:54 ora_cjq0_db2 oracle 2493 1 0 Jul06 ? 1-08:32:16 ora_d000_db2 oracle 2495 1 0 Jul06 ? 1-07:57:46 ora_d001_db2 oracle 2497 1 0 Jul06 ? 00:30:41 ora_arc0_db2 oracle 2499 1 0 Jul06 ? 00:30:08 ora_arc1_db2 oracle 2518 1 0 Jul06 ? 01:14:30 ora_lck0_db2 oracle 2479 1 0 Jul06 ? 00:18:44 ora_ckpt_db2 oracle 963 1 4 Aug22 ? 08:44:46 ora_s000_db2 oracle 9594 1 0 Aug22 ? 01:04:55 ora_s002_db2 oracle 19104 1 0 Aug24 ? 00:20:31 ora_p000_db2 oracle 19106 1 0 Aug24 ? 00:04:51 ora_p001_db2 oracle 19733 1 0 Aug24 ? 00:03:34 ora_p002_db2 oracle 19760 1 0 Aug24 ? 00:03:55 ora_p003_db2 oracle 15724 1 0 Aug29 ? 00:03:23 ora_p004_db2 oracle 12445 1 1 Aug29 ? 00:30:07 ora_s001_db2 Notice the amount of CPU time that the dispatchers require... We run both shared server and dedicated depending upon the SQL... If you can afford the memory, permanent dedicated connections are the way to go. _____ From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Zhu,Chao Sent: Wednesday, August 30, 2006 6:57 AM To: VIVEK_SHARMA Cc: oracle-l@xxxxxxxxxxxxx Subject: Re: Docs, Links, Good Books on Performance with RAC 10.2 / Solaris 10 ? If single instance can suffer from this, so does RAC. RAC can only make the problem worse not better. It is mainly from dispatcher CPU overhead, the oracle dispatcher is much worse than the Solaris OS scheduler. I don't have much document talking about tuning on RAC. Basicly if you tune fine for single instance, RAC is the same, just pay attention to the data partition, which oracle claims it is not needed any longer compared to OPS. On 8/30/06, VIVEK_SHARMA <VIVEK_SHARMA@xxxxxxxxxxx> wrote: Thanks Zhu Chao for the info. 1 Question - If you mean CPU usage DOUBLED when using Shared Servers with RAC ? A basic Qs - Is setting up shared servers for RAC similar to it's setup for single instance (NON-RAC) ? Any Good Docs, Links, Books, metalink Doc IDs, Pointers to Oracle Documentation for Performance with RAC? I will periodically send e-mails on our progress though the benchmark is tentatively planned to start after about 1 month. Regards _____ F -- Regards Zhu Chao www.cnoug.org