Postgres is a great tool for most databases. Larger installations however, pretty much require horizontal scaling; addressing multi-TB tables relies on multiple parallel storage streams thanks to the laws of physics. It’s how all immense data stores work, and for a long time, Postgres really had no equivalent that wasn’t a home-grown shard management wrapper. To that end, we’ve been considering Postgres-XL as a way to fill that role. At first, everything was going well. Performance tests showed huge improvements, initial deployments uncovered no outright incompatibilities, and the conversion was underway.
Then we started to use it.