Oracle Streams

We have production databases on multiple geographical locations. We have to keep our system available on 24 X 7. That's why real time up to date data is necessary across multiple databases. Again, for load balancing, we have multiple web servers and each web server is pointed to a different database - for seamless users transitions, we need all the databases synchronized.

We started data replication with Quest SharePlex software. As our requirement changed and we started using Oracle Enterprise Edition, it's time to migrate to oracle's proprietary technologies like Oracle Streams.

Oracle Streams captures database changes at a source database, stages the changes, propagates the changes to one or more destination databases, and then applies the changes at the destination database(s).

Oracle Streams begins by capturing changes. The changes that take place in a database are recorded in the database redo log files. The Streams capture process extracts these changes from the redo log files and formats each change into a logical change record (LCR). The LCRs are then stored in a queue (staged). Next, Streams propagates LCRs from one queue (the producer queue) to another (the consumer queue) and can then apply the LCRs from the consumer queue to the destination database.

Next few days, I will be learning and experimenting Oracle Streams. Some related articles are-

http://download.oracle.com/docs/cd/B19306_01/server.102/b14229/title.htm
http://www.oracle.com/technology/oramag/oracle/04-nov/o64streams.html