RE: Data Guard to Logical Standby

From: John Hallas <>
Date: Fri, 2 May 2008 08:28:09 +0100
Message-ID: <>

Have you tested the overhead April?

We have been doing some testing and even under very heavy load, Streams keeps up well and whilst it does have an overhead on the primary server it is manageable.

Where we did notice a very large overhead was when we tried streaming to two different databases. Capture once but apply remotely twice. That killed the primary server off. I must admit I was surprised at that as I would have expected the redo logs to have only been mined once (albeit more data captured when dual streaming).  

I did not spend a lot of time tuning and talking to an Oracle consultant he expressed the opinion that there was not a lot of Streams expertise around    

Blog available at  

[] On Behalf Of April Wells Sent: 01 May 2008 22:58
To:; Subject: RE: Data Guard to Logical Standby  

We were "going" to go this route, but the overhead on the OLTP would be "too huge"  

[] On Behalf Of Ben Wittmeier Sent: Thursday, May 01, 2008 4:54 PM
To: April Wells;
Subject: RE: Data Guard to Logical Standby  

You may also want to look into Oracle Streams. It is more flexible than dataguard. For example, you can choose to capture only a specific table's changes downstream.....



[] On Behalf Of April Wells Sent: Thursday, May 01, 2008 9:48 AM
Subject: Data Guard to Logical Standby

We are trying to create a logical standby database (solaris) using data guard so we can use downstream data capture to populate a reporting database (Linux) for historical reporting.  

Any chance anyone has done this and can give me some pointers on what I'm probably going to do wrong?  

Can I set rules up stream on the source database on what tables I don't want to have included in the data guard log apply or will it just apply everything? I'm trying to tough my way through the documentation, and am stuck at the "uniquely identify rows" part. It seems that EVERYONE on the source system has a plan table and that doesn't have a primary key. Do I care? Will it complain?  

Should I create a primary key rely disabled on ALL of those plan tables?  

Thanks for any advice



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Received on Fri May 02 2008 - 02:28:09 CDT

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