Since I store the PID value of the process in a database, this PID might be re-used by the operating system when deleting the record at startup.

Right, but you can check to see if that pid exists, and if so, what process actually holds that pid. If the process that holds the pid is not the same as the process you are tracking, then you can assume that your process was killed abruptly and that you can delete the pid-record and start.