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Looking for a way to synchronize Streams

From: Charles Schultz <>
Date: Thu, 5 Oct 2006 08:29:45 -0500
Message-ID: <>

Oracle OSEE

Some background about our program flow: the Target database is a staging database for EDW ETL, where we use replication and deltas to migrate data from Production. At some point in time, we will maintain two individual APPLY Streams, and we want to be able to checkpoint the Target database for respective processes (ie, apply ETL on certain time-sensitive data, but allow the other Stream to continue APPLY for a different end consumer). But for the sake of being clear, we only have one APPLY stream right now.

Our goal is to be able to synchronize the Target database in a very specific point of time on the source database (a particular SCN). I am told that this will become critical later on, but right now we are able to get by without holding fast to a specific SCN. I have been attempting to do this by tracking the SCN as it comes out of the Source database and into the Downstream database. I just learned yesterday that this SCN is not necessarily the same, hence I had to think about a different approach. I suppose it would be possible to identify the archive log that contains the SCN, and to stop the CAPTURE, PROPAGATE and APPLY processes after it move through. That is probably viable, since we will be switching the archived logs on the Source database at a point in time as a sort of hard checkpoint. But this seems like a less-than-ideal method. Not to mention it is not compatible with our desire to have two APPLY Streams. Can you offer advice for our situation?

In addition, I would ideally like to continue capturing and mining archived logs even while the APPLY process is disabled, due to the resource- and time-intensive operations of mining the logs. So far, we have encountered some problems with this approach because the CAPTURE process is very aware of the state of the PROPAGATE process, and can become partially disabled if too many errors are observed.

Some related but specific questions:
Is there a way to manually reset the limit of errors before the PROPAGATION schedule is disabled?
Can all of the processes (CAPTURE, PROPAGATE, APPLY) be set to automatically restart after an error?

Please excuse my naivete - I kinda had to jump into the frying pan on this one.

Charles Schultz

-- Received on Thu Oct 05 2006 - 08:29:45 CDT

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