study case?

From: Tuning <c_armanet_at_hotmail.com>
Date: Fri, 30 Aug 2002 16:10:04 +0200
Message-ID: <aknu9q$kqi$1@wanadoo.fr>

Hello,

Oracle Enterprise Edition 8.1.7, Win 2K.

I've had a query which was executed with a better explain plan with RBO than CBO (and much faster!)
with stats on date, with compute option of course!; and I made some optimization attempts on init.ora parameters. Finaly, CBO worked well with parameter db_multiblock_read_count from 8K to 16K.

Then, just for testing, I changed this parameter again, and leave it to 8K. So, I was quite surprised when I saw the same explain plan (and fastness) as with 16K!!

Any idea?

Thanks.

Regards,

C.A. Received on Fri Aug 30 2002 - 09:10:04 CDT