Londiste

Londiste is a more recent queue based replication software driven by triggers that's part of the SkyTools project set: http://pgfoundry.org/projects/skytools/

It's one of the database applications written to support scaling up database operations at Skype. Relative to Slony, Londiste has two highly visible advantages. The first is that it targets a smaller feature set and is therefore less complicated to set up. It also has abstracted away the concept of transporting changes from the master to the slaves a bit more cleanly. The Londiste design is based on a generic queue library that is less coupled to the underlying data transport mechanism used in Slony.

Another advantage for Londiste is that it requires minimal locking in order to replicate. Slony has a few situations you might run into where the exclusive table locks are required. An example is moving a replication set from one node to another.

Given the way open source software works, where it's expected...