tl;dr: PlanetScale has launched Neki, a sharded Postgres offering now in platform preview, applying lessons from years of running large-scale sharded MySQL clusters. Unlike Postgres-compatible distributed databases, Neki runs real Postgres on every shard (each with a primary and two replicas across AZs) behind a router that speaks the Postgres wire protocol, preserving extensions and SQL behavior. It supports online workflows for schema changes, upgrades, failovers, and resharding, and can run unsharded initially, letting users reshard later as a workflow against the existing cluster.