What happens when you had something that was set manually but then you disable it on a running server? It depends on the version you're running. Let's say your postgresql.conf file started with the following setting active:
work_mem = '4MB'
You now edit the file to comment that setting out:
#work_mem='4MB'work_mem = '8MB'
And then tell the server to re-read the configuration file:
$ pg_ctl reload
#work_mem is a context setting. Starting with PostgreSQL 8.3, this change will return the value back to the server default (boot_val). And, as of Version 10.0, you'll also get a note in the log file about that:
LOG: received SIGHUP, reloading configuration files LOG: parameter "work_mem" removed from configuration file, ...
