Ack, thank you! The idea was to minimize the operational overhead of logical replication (slot growth, slowdowns from reorder buffering, handling advance schema changes) and reducing load on Postgres. This approach lets us purpose-build replication for ClickHouse. Postgres logical replication was primarily designed keeping in mind with Postgres as the target.

There’s also some interesting work happening in core with a similar goal of decoupling logical decoding from the Postgres process. We plan to share learnings from WalShadow with the core and hopefully help bring this to Postgres someday :) https://hacking.postgres.tv/topics/logical-decoding/