Appreciate you chiming in! We evaluated almost all the FDWs and landed on clickhouse_fdw (built by Ildus) as the most mature option. However, it hadn’t been maintained since 2020. We used it as the base, and the goal is to take it to the next level.

Our main focus is comprehensive pushdown capabilities. It was very surprising to see how much the Postgres FDW framework has evolved over the years and the number and types of hooks it now provides for push down. This is why we decided to lean into FDW than build an extension bottoms up. But we may still do that within pg_clickhouse for a few features, wherever FDW framework becomes a restriction.

We’ve made notable progress over the last few months, including support for pushdown of custom aggregations and SEMI JOINs/basic subqueries. Fourteen of twenty-two TPCH queries are now fully pushdownable.

We’ll be doubling down to add pushdown support for much more complex queries, CTEs, window functions, and more. More on the future here - https://github.com/ClickHouse/pg_clickhouse?tab=readme-ov-fi... All with the goal of enabling users to build fast analytics from the Postgres layer itself but still using the power of ClickHouse!