The database server's message log is a record of all messages recorded by the database server. This is the first place to look if you have server problems, and a good place to check regularly.
This log will have messages in it that look something like the following:
2013-01-29 23:15:41 CET LOG: database system was not properly shut down; automatic recovery in progress 2013-01-29 23:15:41 CET LOG: record with zero length at A/A3478F08 2013-01-29 23:15:41 CET LOG: redo is not required 2013-01-29 23:15:42 CET LOG: database system is ready to accept connections 2013-01-29 23:15:42 CET LOG: autovacuum launcher started
We'll explain some more about these logs once we've located the files.
You'll need ...