Re: Oracle 10g: Advanced Replication and Streams

Comments below should be qualified with "as of 10g":
* According to Oracle Support, Oracle streams will be enhanced
  in future versions.
  Advanced replication will not be enhanced in future versions.
* In 9i, I've read comments by folks stating that Advanced
  Replication is more stable than Streams. In 10g the Streams   has stabilized and matured quite a bit.
* Streams does not support synchronous replication. Advanced

   Replication does. Although one needs to be certifiably insane or    have an excellent network in order to go for synchronous replication.
* Streams does not support BFILEs, REF and nested table types.

   Advanced Replication supports them. However, Advanced    Replication does not support LONG/LONG RAW datatypes,   Streams on the other hand does support them. In future versions, you   can expect streams to support all datatypes.
* Streams has been touted to be better performing than Advanced

   Replication. I personally have never compared them in terms of    performance, although based on the architecture, I'd be inclined    to think that Streams has better performance.
* Advanced Replication requires a master definition site. In streams,
  all sites are master definition sites .. by definition.
* Streams is more advanced and flexible than Advanced Replication.

   For example: You can replicate a portion of a table in Streams.    In Advanced Replication you have to replicate the whole table.    In fact in Streams the structure of the table in the two databases    can be different also (for example col1, col2 being replicated from    databaseA and col3, col4 being replicated from databaseB).
* Advanced Replication is only for replicating data. Streams can be for
  replicating data, messages etc.
* Advanced Replication can replicate data from and Oracle database to
  an Oracle database only. Streams can be used to replicate data from   an Oracle database to a non-oracle database also.
* Oracle provides a script/utility to convert an Advanced Replication
  environment to a Streams env. In terms of high level API's, Streams   replication looks similar (although much better) to MM Replication.   Although, in terms of difficulty of managing or installing, I do not   believe Streams is easier to install or manage than Advanced   Replication. All the basics of Conflict resolution are exactly the   same in both environments. Conflict resolution strategies are what   make a replicated environment slightly difficult to build and manage.

There are probably lot of other differences. However, I'd suggest that unless you have a compelling reason, there is no sense in using Advanced Replication in databases 10g and higher. You should be using Streams which is being actively enhanced and provides much more flexibility than Advanced Replication.

HTH Anurag Received on Mon Apr 03 2006 - 12:49:02 CDT