Monday, June 10, 2013

Oracle Streams vs Advanced Replication

Streams is a much more efficient architecture. Rather than synchronously capturing changes in materialized view logs which adds overhead to the transaction, Streams mines the redo logs that are generated by the change in order to generate the change vector to send to the target system. That also allows the change to be replicated to the other system(s) much more quickly.

Streams is a much more flexible architecture. You can write your own custom apply processes which makes it relatively easy to inject additional processing or logging, to ignore certain changes, etc. You can send a Streams logical change record (LCR) to a JMS queue or to a non-Oracle system (though, of course, you'd need to write code to apply the LCR on the non-Oracle system).

Oracle Streams does not support the following:
  • Replication of changes to tables with columns of the following data types: BFILE, ROWID, and user-defined types (including object types, REFs, varrays, and nested tables)
  • Synchronous replication
If your current Advanced Replication environment uses these features, then these elements of the environment cannot be migrated to Oracle Streams. In this case, you might decide not to migrate the environment to Oracle Streams now, or you might decide to modify the environment so that it can be migrated to Oracle Streams.

No comments:

Post a Comment