Hi @certificatemanager_4002 ,
From the cybersecurity perspective, it's fine to leave it as root since the core process is run by the non-root user postgres inside of the container. You're never exposing a network service while the containerized process has root privileges.
Here is more information on this if you're curious:
https://stackoverflow.com/questions/73672857/how-to-run-postgres-in-docker-as-non-root-user
As you can see in that link, it's technically possible to configure as non-root, but it requires more effort and doesn't really get you any benefit.
As for load-testing and restarting, it really depends on the hardware and similar factors. Keep in mind that InedoDB is simply the postgresql container image with some minor configuration tweaks/changes. So any question you ask about InedoDB you can really ask about postgresql as well.
As for using an external PostgreSQL server, the only information we have at this time is in the link I sent you before. You really need to be an expert on PostgreSQL if you wish to run your own server.
Thanks,
Alana