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Re: Problems with Opinions

From: <>
Date: Fri, 9 Jun 2000 13:07:07 -0500
Message-Id: <>


I have not been a dba too long, but having been on both sides of the fence (dev and dba) I can say with all sincerity that over 90% of performance problems come from the database design and the code. The database can not make up for a bad design or poor code. This is not a 'support' answer. This is reality !!

For example: One of our data marts was designed very poorly. These people
(CONSULTANTS) thought that writing the reports would be the easiest part.
Granted writing loads are not easy but when your report has to go through many, many gyrations in ONE SQL STATEMENT to return results, it will never be fast. Ever. The bottom line is that the consultants (and one employee) who designed the database had no idea what exactly the reports would be doing. I was thrown on the reporting team after the design was locked in and people expected miracles from me. No dice, man!! I have never seen an explain plan that went over 32 loops deep before. I modified the design a bit, and got a small bit of performance gain, but the underlyng problem was still there: I had to do a UNION ALL and hit the fact table twice - not necessarily on the partition key, do many subselects for uniqueness, apply row level security and sometimes retrieve data from the warehouse in each report. The result: Very poor performance, an expensive application, complaining customers and no monetary ROI.

However, my interest in the problems of this app, the database design, fighting for a modification in a room of 13 men, tuning SQL statements, etc. primed me to be promoted to dba.

Does that make sense?

"cyril" <> on 06/09/2000 11:02:34 AM

Please respond to

To: Multiple recipients of list ORACLE-L <> cc: (bcc: Lisa Koivu/GELCO)

Subject: Problems with Opinions


  I have been a DBA for 1 and half years now and now I am facing a serious credibility crisis!!

  We have upto 70GB databases and after seeing their performance (in RULE based)
  we have convinced ourselves that 'may be others out there also are living with this performance'...
  but now I hear of people having 50-100GB databases 'available' on net...

  Can some one please explain how that is being managed?

  'cos based on my observation of client-server I was pretty convinced that Oracle Web Server

   is a good 'toy' .. which however will crash on 'seeing load'...

.. Can some one please help me 'understand' HOW this is being achieved..


PS: Please don't give me Oracle Support 'type' answers saying 'application' has to 'tuned' Database

        Instance 'has to be tuned' etc...
        I am looking for a 'real' way of handling my problem!!!!!

      +  I am (ever!) curious to know if anyone has successfully gone from
RULE based to COST based...
          If so I am keen to know  HOW they did it.. and what were the
problems encountered...!!
Author: cyril

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Received on Fri Jun 09 2000 - 13:07:07 CDT

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