This mode doesn't require modifications in the client code.
Limitations:
Asynchronous querys aren't supported.
This mode doesn't require modifications in the client code, but it assumes that modifications on the databases are going to be replicated some way.
Limitations:
Asynchronous querys aren't supported.
This mode requires that the client code use a different connection for reads and for writes. Each of the connections has to be done against a different DBBalancerDaemon, each one listening in a different port and configured with different parameters (one "-r", the other "-w").
Limitations:
Replication support isn't completely finished. While it should somewhat work, errors aren't still very well managed.
Asynchronous querys aren't supported
OID's returned from a writer daemon shouldn't be relied to be valid when they come after a INSERT or UPDATE operation, as it's very probable that they're different across the different backends. The daemon will always return OID's from the first backend.