thread safe MySQLdb cursors?

[Steve Strassmann]

I've been using MySQLdb in Python for a while with no problems.
I'm using it in an SCGI web server (Apache forwards all requests
to a standalone process running Python/SCGI)

But recently, I've started getting SQL errors, it seems
like my Ajax callbacks are stepping on each other in some
clear violation of thread safety.
Here is a greatly simplified description:

callback1.py is invoked via SCGI
it calls GetMyColorFromSQL()
this creates a cursor with MySQLdb.connect() and
reads a string from the database.


callback2.py is invoked via SCGI
it calls GetMyLengthFromSQL()
this creates a cursor with MySQLdb.connect() and
reads an integer from the database.


What happens is that GetMyLengthFromSQL() calls
cursor.execute(sql, params)
cursor.fetchall()
which returns the strings which are clearly from the other call.


I'm sure the solution lies in some careful management of the
MySQLdb cursors, but I can't find any documentation explaining
what to do. I am careful to create exactly one cursor in each
callback and re-use it throughout the callback.


I tried calling cursor.connection.close() at the end of each callback
and started getting these errors:
Exception _mysql_exceptions.OperationalError: (2006, 'MySQL server
has gone away')

Is there any thing you can think of that I should be doing or
looking at to make these threads more robust?