I have MySQL running behind Infoglue for a new web app one of my clients has. We went into production on Friday with that web site. Saturday evening the hosting providing had a scheduled update and so all the boxes got rebooted. Unfortunately, the MySQL service which was configured to autorestart didn't come back up. In the application event logs (I've got it running on a Windows server) it said:
...MySQL Server 5.1\bin\mysqld: unknown option '--enable-pstack'
I searched the MySQL forums and Google for this error and nothing. I reinstalled the service a couple of times.. and nothing - same error. I was sweating by this time.
Then I started looking at the my.ini file for Mysql in the installation folder (sibling of the bin folder). I saw these lines at the very bottom:
#Print a symbolic stack trace on failure.
Ah ha. So here's where that 'unknown option' was coming from. I had no idea what was making a failure happen on startup to make it print out this 'stack trace' so I just commented out that line. ...And low and behold, MySQL started up happily and things worked.