The main configuration file for PostgreSQL is postgresql.conf, a text-based file that drives the cluster when it starts.
Usually, when changing the configuration of the cluster, you have to edit the postgresql.conf file to write the new settings and, depending on the context of the settings you have edited, to issue a cluster SIGHUP signal (that is, reload the configuration) or restart it.
Every configuration parameter is associated with a context, and depending on the context, you can apply changes with or without a cluster restart. In particular, available contexts are the following:
- internal: A group of parameters that are set at compile-time and therefore cannot be changed at runtime.
- postmaster: All the parameters that require the cluster to be restarted (that is, to kill the postmaster process and start it again) to activate them.
- sighup: All the configuration parameters that can be applied with a SIGHUP signal sent to the postmaster...
