This sounds great! I'm no expert but it seems that the postgres documentation disagrees about the process for enabling the extension -- "The module must be loaded by adding pg_stat_statements to shared_preload_libraries in postgresql.conf, because it requires additional shared memory. This means that a server restart is needed to add or remove the module."[1]
What I was really looking for was a ballpark estimate or guideline of what additional resources a server would need to run this extension.
It admittedly does vary based on the way you installed Postgres. Not all, but many installation methods already come with it in the shared_preload_libraries. You still have to run create extension for it to exist or it has to be enabled by the superuser. Postgres.app for example on the mac already has it there but you still have to run create extension.
What I was really looking for was a ballpark estimate or guideline of what additional resources a server would need to run this extension.
[1]https://www.postgresql.org/docs/11/pgstatstatements.html