Reads do involve making some network round-trips, but it's only a few milliseconds and there's no specific throughput limitation. Write throughput is limited by

Reads do involve making some network round-trips, but it's only a few milliseconds and there's no specific throughput limitation. Write throughput is limited by network latency. There is also a relaxed consistency mode in pg_paxos, which avoids making round-trips on reads, but might give stale results in case of failure.