Enable Constraint

From: Erik Williams <ewilliams_at_brownco.com>
Date: Wed, 19 Dec 2001 11:59:54 -0800
Message-ID: <F001.003E08AB.20011219113629@fatcity.com>

I am having problems re-enabling a foreign key constraint on a large table. The table with the foreign key constraint has 20M rows and the parent table has 1M rows. The foreign key constraint references the primary key of the parent table. I am surprised that the re-enabling is taking so long - 25minutes. I thought that for each record in the foreign key table, a lookup would be done for the existence of a corresponding primary key in the parent table. I though that this should be relatively quick due to the fact that the column is a primary key and therefore indexed. Am I missing something here? Am I being too critical of the time it takes to do 20M index lookups? Am I mistaken about how a foreign key constraint is re-enabled?

Any thoughts would be much appreciated.

Thanks
Erik  

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Author: Erik Williams
  INET: ewilliams_at_brownco.com

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