Interesting! How does it compare with ducklake?

You could say

With DuckLake, the query frontend and query engine are DuckDB, and Postgres is used as a catalog in the background.

With pg_lake, the query frontend and catalog are Postgres, and DuckDB is used as a query engine in the background.

Of course, they also use different table formats (though similar in data layer) with different pros and cons, and the query frontends differ in significant ways.

An interesting thing about pg_lake is that it is effectively standalone, no external catalog required. You can point Spark et al. directly to Postgres with pg_lake by using the Iceberg JDBC driver.