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

  • From: "Wales, Stephen (RTSI)" <Stephen.Wales@xxxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Fri, 2 Apr 2004 15:02:23 -0700


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 =
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, =
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 =
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 - =
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 =
small percentage of queries as they come in and tune them as they =

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


-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of DENNIS WILLIAMS
Sent: Friday, April 02, 2004 2:43 PM
To: 'oracle-l@xxxxxxxxxxxxx'
Subject: RE: The Oracle Optimizer - are there problems with it?

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