Re: Snapshot log overhead

From: <dpurrington_at_my-deja.com>
Date: Mon, 22 Nov 1999 12:39:45 GMT
Message-ID: <81bdih$rjn$1@nnrp1.deja.com>

Thanks for the reply. Actually, what I'd like to know is what is the overhead involved with performing an insert during any write transaction. My understanding is that when you update a record, Oracle records the rowid of the changed record and the timestamp of the new transaction. There has to be some overhead for that transaction.

You wrote:
> I think your question though is really more pointed toward when does
> trigger based replication become an overhead compared to log based
> replication, like SharePlex or Oracle's own standby database. That is

What I'm comparing it to is the Shareplex product. According to Quest, this is NOT a trigger-based replication mechanism. It monitors the redo logs and passes the information to the replicated system. Therefore, it has no interaction or impact on the monitored RDBMS (aside from the indirect impact via the CPU cycles necessary to monitor the log file, queue it, etc.). It does have some functional drawbacks though (you can't replicate horizontally).

But both solutions are the incremental or "fast" refresh type of replications.

I hope this clarifies the question! Thanks for your help.

Dave

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Before you buy. Received on Mon Nov 22 1999 - 06:39:45 CST