[pysqlite] database locked

File "/usr/lib/python2.5/site-packages/tpblue/sql_db.py", line 412, in initia
l_insert     self.connection.commit()
internal_process_message 98: 1:1: filter out: OperationalError: database is locked

trying to debug some long-running code, I started getting these kinds of errors.
 In googling, it sounds like that in the database was locked for a very long
time and that something else is clearly wrong.

What I need is to know how to detect these errors via exceptions so I can employ
an appropriate strategy for recovering from them.  Heck, I think I need to
figure out why they happened so I can figure out better ways of preventing them. :-)

are there any tools for detecting what's causing this kind of error?