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RE: powerbuilder in rbo and multiple constraint question...

From: Kevin Toepke <ktoepke_at_rlcarriers.com>
Date: Thu, 15 Jan 2004 07:34:50 -0800
Message-ID: <F001.005DCED8.20040115073450@fatcity.com>


Chris

I know from a previous assignment that PowerBuilder has no issues running queries against a database using the CBO. In fact, PowerBuilder doesn't give a rats backside what the database does to the query as long as it returns what's expected.

As for "redundant" constraints, they will increase the parse time for all sql commands and slow down all DML operations -- just as they do in SQL Server.

HTH
Kevin

-----Original Message-----
Sent: Thursday, January 15, 2004 9:55 AM To: Multiple recipients of list ORACLE-L

I'm working with a 3rd party vendor to resolve some performance issues with there call center app. The app is written in PowerBuilder. When I traced the offending sessions, I noticed the queries are being run under the rbo. When I run those same queries under the cbo the response time is dramatically different. I asked why they insisted on running under the rbo. There response was that it's a limitation of powerbuilder. I don't buy that for a second. ...anyone know for sure?

.and on a side note...my company is developing a call center app in .not. The dba's were conveniently left out of the design process. I just took a look at the schema they are using and noticed redundant constraints on almost every table. i.e. not null, primary key, unique on the same column. Before I investigate myself with a 10046, does anyone know if oracle has to do multiple recursive sql to validate each constraint or is it smart enough to know they are redundant and only validate the pk constraint? ........when I saw this, I blasted the developers (admittedly some misdirected aggression) for not having a clue what they were working with and blankly stated that the redundant constraints (among other things if found...no bind variables for one) would negatively affect performance. .after possibly putting my foot in my mouth I'm looking to validate what I said. ...if I don't get any responses to this, I'll run the trace myself and post my findings. ....oh yeah...the .not developers responded by saying the redundant constraints wouldn't be a problem in sql server. ...something I'm almost positive they haven't validated either.

Thanks!
chris

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Author: Chris Stephens
  INET: ChrisStephens_at_affina.com

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Author: Kevin Toepke
  INET: ktoepke_at_rlcarriers.com
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San Diego, California        -- Mailing list and web hosting services
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