RE: bandwidth to physical standby..

From: Justin Cave (DDBC) <jcave_at_ddbcinc.com>
Date: Thu, 27 May 2004 12:09:32 -0600
Message-ID: <87E9F113CEF1D211A4C30090273018742BCB6B@ddbcinc.ddbc.local>

Frequently, you can tune your system to generate less redo, which is often a lot easier than trying to compress the archived log files in transit. For example, if you replace a cursor FOR loop updating a number of rows with a single UPDATE statement, you will see a significant reduction in redo generation.

CREATE TABLE x
AS
SELECT * FROM all_objects;

Run a couple of iterations of the INSERT to get a bunch of data in the table

INSERT INTO x
SELECT * FROM all_objects;

The statement

UPDATE x

SET object_id =3D object_id + 1;

Generated 85.4 Mb of redo on my system

The PL/SQL block

DECLARE=20
CURSOR c1 IS=20
SELECT *

      FROM x
       FOR UPDATE;

BEGIN
  FOR x IN c1
  LOOP
    UPDATE x

       SET object_id =3D object_id - 1
     WHERE CURRENT OF c1;

END LOOP;
END;=20 Generated 153 Mb of redo, an 80% increase

Justin Cave
Distributed Database Consulting, Inc.
http://www.ddbcinc.com/askDDBC

-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Murali Vallath Sent: Thursday, May 27, 2004 9:55 AM
To: ORACLE-L
Subject: bandwidth to physical standby..

Is there any method within Oracle to reduce the bandwidth of data transfers between the primary and the physical standby database.
=20

We have to pay by the bandwidth to the hosting provider and trying to see if we had an option to reduce the bandwidth...
=20

also it would be great to know if any gotchas with such reduction in bandwidths..
=20

TIA
=20

Murali

=09

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Received on Thu May 27 2004 - 13:02:54 CDT