"Slony-I is undoubtedly our most popular replication tool. It supports Master-Slave High Availability Replication. However, there are a number of other solutions, such as dbMirror, eRServer, pgPool, C-JDBC, and the proprietary Mammoth Replicator, all of which are in wide use because they solve different replication problems than Slony-I does. Replication is not a single solution for a single problem; it is several solutions for a wide array of different problems. That's why no one replication tool will ever be the "default" replication for PostgreSQL."
I believed well before then it was a fallacy and a bad community decision to not put support behind a single, integrated solution. I also believe it has been one of the single most important policy failures of the .Org community and has lead PostgreSQL to grow much more slowly than it otherwise could have.
From a business standpoint it opened the door for many other solutions, a lot of learning experiences and a lot of professional services consulting (Thank you: Slony). It also opened the door for the only solution to look at being integrated into Core. Mammoth PostgreSQL Replicator (Replicator).
Replicator opened the door for CMD in many ways. Although it was never a huge commercial success we did have early customers (Cisco) and there was quite a few deployments over time. Eventually, we Open Sourced Replicator hoping to generate some external interest, and although quite a few hackers talked to me about participating, none of it actually materialized into anything useful.
To this day, nothing can touch the usability of Replicator for PostgreSQL replication. It is the easiest to configure, the easiest to run, the easiest to manage. Alas that is not enough, as we needed to re-architect to eliminate the one single point of failure (as well as some other issues, crash safety I am looking at you). Further with the emergence of the Hot Standby technology that is in 9.0, the need for Replicator has become even less.
Although there were design decisions originally made that were incorrect, I still believe that the overall architecture of Replicator was sound. Implementation, perhaps not but architecture yes. I also believe that the in development version (1.9) would have been a game changer as a whole. Unfortunately we were not able to execute for a number of reasons that don't really matter anymore.
Everyone who worked on replicator should be proud of what they did. It should be looked on as a learning experience. We built something, nobody else did, even now. We built integrated and flexible PostgreSQL replication. Was it perfect? No. Should we have open sourced it sooner and tried harder to integrate it into the community? Probably. Were there design decisions that should have been different? Yes. Were there components we should have changed (MCP SPOF)? Yes.
Of course, we can say all of that about the current state of PostgreSQL. Let alone Replicator, Slony or any other project. Just read -hackers. We are not perfect, but our team did something good.
It took until 2010, 7 years? after Replicator first released for the community to figure out they were wrong. We were pioneers for PostgreSQL and our team should be proud of that.
1. http://archives.postgresql.org/pgsql-advocacy/2004-11/msg00063.php