That's right! Greenplum is still active, but falling off.

We see pg_analytics as the next-generation Citus columnar, with much better performance and integration into the wider data ecosystem via Delta Lake, and eventually Iceberg

I've been scanning through the comments looking for the opportunity to ask, while not seeming critical...

why start with Delta Lake instead of Iceberg?

I imagine it might have had something to do with timing and the state of Iceberg at the time you started this effort?

You're exactly right. There is a mature project called delta-rs which we use. The Iceberg equivalent, iceberg-rs, is still very young. We are planning to contribute to it and eventually add support for Iceberg