Awesome to hear more about MySQL/Vitess connection pooling.
Folks typically only consider memory usage for database connections, but we've also had to consider the p99 latency for establishing a connection. For SpiceDB[0] one place we've struggled for our MySQL backend (originally contributed by GitHub who are big Vitess users) is preemptively establishing connections in the pool so that it's always full. PGX[1] has been fantastic for Postgres and CockroachDB, but I haven't found something with enough control for MySQL.
PS: Lots of love to to all my friends at Planetscale! SpiceDB is also a big user of vtprotobuf[2] -- a great contribution to the Go gRPC ecosystem.
[0]: https://github.com/authzed/spicedb