With the exception of the three configuration variables described here, ProxySQL will only parse the configuration files the first time it is started, or if the proxysql.db file is missing for some other reason.
If we want to change any of this data we need to do so via ProxySQL’s admin interface and then save them to disk. That’s fine if ProxySQL is running, but what if it won’t start because of these values?
For example, perhaps we accidentally configured ProxySQL to run on port 3306 and restarted it, but there’s already a production MySQL instance running on this port. ProxySQL won’t start, so we can’t edit the value that way:
2018-10-02 09:18:33 network.cpp:53:listen_on_port(): [ERROR] bind(): Address already in use
We could delete proxysql.db and have it reload the configuration files, but …[Read more]