RE: two instance -- one database

From: Mercadante, Thomas F (LABOR) <>
Date: Wed, 24 Sep 2008 13:01:24 -0400
Message-ID: <ABB9D76E187C5146AB5683F5A07336FFE092E4@EXCNYSM0A1AJ.nysemail.nyenet>


Have you tested a multi-table join across the database link?

Pick two very large tables.

Create a query and run it on the source database with timing turned on.

Run the same query on the remote database and compare the timings.  

This used to be a very big issue. The "where" clause used to be executed locally which means that all data from both tables was brought across the database link and joined locally. A very bad arrangement.  

I agree with Tim Gorman. It accomplishes nothing and adds complexity at your personal cost. You will be tuning this arrangement forever.


[] On Behalf Of Brady, Mark Sent: Wednesday, September 24, 2008 11:07 AM To: oracle-l
Subject: two instance -- one database  

I have a friend (no really, this isn't some lame way of telling you about me but trying to hide that by ... )    

I have a friend, and at his company they have an Oracle database with tables and data. We'll call it Database A and they have another Database B that has views across dblinks to each of the tables in Database A. The data team says that this protects Database A from bad queries.  

So can anyone think of any possible benefit from this arrangement? Will administration be easier, queries faster, performance more predictable? Anything?  

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Received on Wed Sep 24 2008 - 12:01:24 CDT

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