Re: Parse overhead on Disabled constraints

From: Davide Bellesi <davide.bellesi_at_visto.com>
Date: Thu, 07 Sep 2000 02:26:18 -0700
Message-Id: <10612.116381@fatcity.com>

Hi, instead of talking about the performace overhead caused by enabled co= nstraints i want to give you a simple example describing a worst scenario=  :

Suppose to have a table A with a foreign Key on the field a1 pointing to = the field b1 of table B

Suppose to delete N record from the table B If the field a1 wasn't indexed you would wait for N full table scans on A

Hope this helps
Davide

-----Original Message-----
From: MVallath_at_cs.com
Sent: Wed, 06 Sep 2000 21:20:28 -0800 To: ORACLE-L_at_fatcity.com
Subject: Parse overhead on Disabled constraints

What is the performance overhead (if any) on disabled constraints? My=20 assumption is that Oracle will have to validate if a constraint is availa= ble=20
and what the status is (ENABLED OR DISABLED). There should be a performa= nce=20
impact, with having=20
constraints in ENABLED state

         Vs=20
        having constraints in DISABLED state=20
         Vs=20
        No constraints or constraints dropped.

Any ideas or stats on this subject.

Thanks

Murali Vallath

--=20
Author:=20
  INET: MVallath_at_cs.com

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