Re: DB Links

Hi,
If you do a fetch through a dblink, even when the dblink is pointing to your own database, you'll see it can take about 6x times, depending on your test.  

The point is you should not get data from database link, you only should get results, when possible.  

To get data from the remote database, try moving the procedure to the remote database and recive ONLY the result.
Try creating a function table, to minimize the join work, to join with a prejoined table.
try the driving site hint.
create a local materialized view from data in remote database  

Juan Carlos Reyes Pacheco
OCP
-------Original Message-------
 

From: klange_at_ppoone.com
Date: 09/22/04 17:45:59
To: Oracle-L (E-mail)
Subject: DB Links  

Does anyone happen to have a reasonable explaination on what happens to a query when you try to access tables accross db_links ?? Does it still use the indexes on the remote machine ?? Does it bring all the data locally into temp tables ??  

Any info will do. Book names .... Actual explainations ... directions to web sites ... Anything.  

We have a procedure, a fairly complex procedure, that takes about 13 hours to run when it is ran against tables that exist accross a DB link. But, when we copy all the tables locally, it runs in about an hour. We would like to try and find a way to fix this. But first, I need to know exactly what is happening when the cursor access those linked tables.  

Any help would be appreciated.  

Kevin
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http://www.freelists.org/webpage/oracle-l Received on Wed Sep 22 2004 - 17:05:55 CDT