This is really cool, I love the idea of combining partitioning with foreign data wrappers to get sharded Postgres. I have tried it before and hit the same issue from the article:
> However, on closer inspection, we can see that we didn’t perform an async foreign scan, but executed each statement serially. Currently (based on my read of the PostgreSQL docs and code), PostgreSQL does not support async foreign scans with a “Merge Append” node (e.g., running multiple operations that require merging sort results, such as a K-NN sort).
It feels like Postgres is quite close to do that in an optimal way.
> However, on closer inspection, we can see that we didn’t perform an async foreign scan, but executed each statement serially. Currently (based on my read of the PostgreSQL docs and code), PostgreSQL does not support async foreign scans with a “Merge Append” node (e.g., running multiple operations that require merging sort results, such as a K-NN sort).
It feels like Postgres is quite close to do that in an optimal way.