Comment by hasyimibhar

What about Multigres[0]? It builds on top of Postgres and adds HA (based on Flexible Paxos[1]), sharding, etc. They're still not production-ready, but I'm highly optimistic they will solve a lot of the problems Postgres have.

For example, with Multigres, you should be able to achieve true zero downtime major version upgrade by simply resharding [2]. With vanilla Postgres + pgBouncer, you can only achieve near-zero downtime (few seconds at most), though it's probably good enough for most use cases.

[0] https://multigres.com/

[1] https://fpaxos.github.io/

[2] https://multigres.com/docs#migrate-across-postgres-versions