When it comes to highly available database servers and configurations, a very important aspect is whether or not a changed setting requires a database restart before taking effect. While it is true that many of these are important enough that they should be set correctly before starting the server, sometimes, our requirements evolve.
If, or when, this happens, there is no alternative but to restart the PostgreSQL service. There are, of course, steps we can take to avoid this fate. Perhaps an existing server didn't need the WAL output to be compatible with hot standby servers. Maybe we need to move the log file, enable WAL archiving, or increase the number of connections.
These are all scenarios that require us to restart PostgreSQL. This recipe will demonstrate how we can avoid this by identifying these settings early on and...
