I don't mean to knock redis. I love redis. I implore you to benchmark Redis in FSYNC_ALWAYS vs Postgres. I encourage you to benchmark it as well with FSYNC_EVERYSEC and understand the tradeoffs that makes - Postgres is still very competitive with EVERYSEC in most workloads, and with a lot less tradeoffs in data reliability.

Yeah, in-memory. That should tell you it's not a persistent data store.