I'm curious why the test needed so many router hosts:
512 shards, each with one Postgres primary each on an r8g.16xlarge
480 Neki routers, each on its own 8xlarge instance
That's ~250K queries/sec per router which seems lowish for this type of workload? The routers won't be doing very much (parse query, route it to proper shard?).
that's over 13k queries/sec per router core, about 50% of it is spent doing syscalls, the other 50%: parsing, doing grpc, tls, go gc, resolving the shards, waiting for the responses
neki is still in platform preview, this experimentation allowed us to collect profiles at such scale and ship some nice optimizations, more are coming