RE: Database link performance

Use a 10046 level-8 trace, and the resulting trace file will show what is significantly impacting your time. I would expect it's either the time tallied to "SQL*Net message from dblink" or a difference in execution plans.    

Cary Millsap

Hotsos Enterprises, Ltd.

cary.millsap_at_hotsos.com

http://www.hotsos.com <http://www.hotsos.com/>  

-----Original Message-----
Rosenblum
Sent: Tuesday, June 04, 2002 11:18 AM
To: Multiple recipients of list ORACLE-L  

Hi,  

Could anybody help me with the database link problem?  

I have two databases db_A and db_B, and link from db_A to db_B.  

In the database db_B there is table B with 1.6 million records.  

I created simple test to query data from the table B via database link
(I am connected to db_A)

declare

   v_record B%rowtype;  

   cursor cB

   is

   select *

   from B_at_db_B.mycomp.com

   where rownum < 20000;

begin

   for c in cB

   loop

     v_record :=c;

   end loop;

end;

I tried to check performance of data querying through the link, so I had two tests:

• via the link - 19.8 sec
• locally - 1.5 sec

Difference is too large, as far as I can expect! I have been REALLY surprised.  

At this time there was mostly no other activity on the network
(databases are on the same subnet, at the same hierarchical level).
 

Could anybody explain is it normal results?  

Thanks,  

Michael Rosenblum,

Dulcian Inc.

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Author: Cary Millsap
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