In versions before 8.3, autovacuum mentioned when it was visiting each database in the logs but not much information beyond that. It's possible to watch it more directly by setting:
log_min_messages =debug2
But, be warned this level of debugging could potentially log a line or more for every statement your server executes, which is both a major performance drag and a source for running out of disk space. It's generally practical to use this much logging to track down an autovacuum problem only when you know the server is nearly idle.
In current versions, you can easily monitor the daemon's activity by setting log_autovacuum_min_duration to a number of milliseconds. It defaults to -1, turning logging off. When set to a ...
