I uploaded most of our Workspace setup here: https://github.com/jschaf/bazel-postgres-sketch. The tooling is a bunch of Go to manage the Postgres process. Basically, give it schema files and receive a running database with a tear down command.

We make temp instances of Postgres quickly by:

- avoiding Docker, especially on Mac

- keeping the data dir on tmpfs

- Disable initdb cleanup

- Disable fsync and other data integrity flags

- Use unlogged tables.

- Use sockets instead of TCP localhost.

For a test suite, it was 12x faster to call createdb with the same Postgres cluster for each test than than to create a whole new db cluster. The trick was to create a template database after loading the schema and use that for each createdb call.