alt Hacker News> and it has no way to serialize a query plan to some form that can be shared between processes
https://www.postgresql.org/docs/current/parallel-query.html
"PostgreSQL can devise query plans that can leverage multiple CPUs in order to answer queries faster."
Nothing to do with plan caching, thats just talking about plan execution of parallel operations which is that thread or process based in PG?
If process based then they can send small parts of plan across processes.