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RE: The Oracle Optimizer - are there problems with it?

From: Wales, Stephen (RTSI) <>
Date: Fri, 2 Apr 2004 15:02:23 -0700
Message-ID: <>


Anything is possible. All I'm going by is what the users are telling = me. =20
They swear that query X ran in 10 minutes 2 weeks ago and now runs in=20 30+. They *swear* that they haven't done anything to change the query = in
question so it *must* be a database issue. (Anyone else ever heard that one before?)

But, since I'm not involved in the query development / testing process, = I
can't be sure about anything and just have to take them at least=20 partially on their word.

As I mentioned previously, I'm not horribly concerned about what I've = seen=20
to date as each of the queries they've brought to my attention has been=20 horribly inefficient as it is and in serious need of some attention - = not
all of the ad-hoc query developers have a good understanding of the=20 inter-relationships between the various tables and the query performance sometimes suffers because of it.

It was a shout in the dark just seeing if anybody was aware of any known deficiencies in the Optimizer in At least that way, I can talk =

to management (who hear of the complaints) and say that I've done my=20 research via Metalink and a community of professional peers, etc.

We update our statistics regularly and I'm more than happy to examine = the=20
small percentage of queries as they come in and tune them as they = arrive.

Thanks to all who have commented to date and thanks in advance for any = other
comments that may be yet to come!


-----Original Message-----

[]On Behalf Of DENNIS WILLIAMS Sent: Friday, April 02, 2004 2:43 PM
To: ''
Subject: RE: The Oracle Optimizer - are there problems with it?


   So . . . if a lot of these queries are new, with evolving queries -- = is
it just possible that it really has nothing to do with the = patch,
but just coincidentally some queries started showing up after the patch? = By
the way, adding that patch produced no complaints on my systems.

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Received on Fri Apr 02 2004 - 15:59:29 CST

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