Buildbot requires a connection to a database to maintain certain state
information, such as tracking pending build requests. By default this is
stored in a sqlite file called 'state.sqlite' in the base directory of your
master. This can be overridden with the db_url parameter.
This parameter is of the form:
driver://[username:password@]host:port/database[?args]
For sqlite databases, since there is no host and port, relative paths are
specified with sqlite:/// and absolute paths with sqlite:////
c['db_url'] = "sqlite:///state.sqlite"
c['db_url'] = "mysql://user:pass@somehost.com/database_name?max_idle=300"
The max_idle argument for MySQL connections should be set to something
less than the wait_timeout configured for your server. This ensures that
connections are closed and re-opened after the configured amount of idle time.
If you see errors such as _mysql_exceptions.OperationalError: (2006,
'MySQL server has gone away'), this means your max_idle setting is
probably too high. show global variables like 'wait_timeout'; will show
what the currently configured wait_timeout is on your MySQL server.