Yes, you're right about ALTER SYSTER. Unfortunately, the op provided neither PostgreSQL version or O/S, so we can't even be sure that isan option. That is why I stated "I cannot confirm".
Thought it was just a non-desire since your solution wouldn't work on any version or O/S...the later of which has zero bearing on the question at hand unless you wish to provide an example of how to manually edit the postgresql.conf file.
David J.
