Well, pg_mooncake is a Postgres extension. So it's really just Postgres :)

We embed DuckDB in our extension as the vectorized execution engine on columnstore tables.

Why rebuild a vectorized execution, when DuckDB has a lot of GREAT properties for this workload (similar syntax to Postgres, embedability).

Here's our architecture: https://www.mooncake.dev/blog/how-we-built-pgmooncake

oh and I totally forgot. pg_mooncake is actually faster than DuckDB on parquet.

We implement segment-elimination to do so. We even blogged about it: https://www.mooncake.dev/blog/duckdb-parquet

Yes but this is an extension that enables abstracting that away for an end user and allows them to just use psql