IE, Zope 2.7.6, Python 2.4.1, MYSQLDA 2.0.9 One of our developers is reporting a curious problem, which I have not been able to track down. It appears to be threading related, somewhere in the ZBMYSQLDB adaptor. The database connection string is bare of transaction indicators. The database is local. All tables are MyISAM which is non-transactioal. Unfortunately the user does not remember the exact sequence of events which generate the problem so I am unable to duplicate. What we do know is that the problem occurs at the beginning of a development session begun with a cold boot of the client machine and a fresh browser and it occurs once and only onece during the development session. The developer normally has two active Zope threads going--one working with the application and one working with the ZMI. He moves between them using the Open/View tab and other buttons. He reports that the first time he moves focus from the ZMI to the application, he gets the following error: ------------------------------------------------------------------- Time 2005/06/20 07:12:03.478 GMT-7 User Name (User Id) XXXX (XXXXX) Request URL http://xxx.xxxxxxxx.com/logged_in Exception Type error Exception Value release unlocked lock Traceback (innermost last): * Module ZPublisher.Publish, line 107, in publish * Module Zope.App.startup, line 222, in commit * Module ZODB.Transaction, line 260, in commit * Module ZODB.Transaction, line 377, in _finish_many * Module Shared.DC.ZRDB.TM, line 59, in tpc_finish * Module Products.ZMySQLDA.db, line 376, in _finish error: release unlocked lock -------------------------------------------------------------------- The lock being released is a transactional lock. None of our locks should be transactional locks, given our setup. I traced through the __init__() method for DB and did not see how transactional locking could be specified so the lock relaease code could run--I must be missing something. No thread in our system uses transactional locking as the tables do no support transactions. The logged_in method references the MySQL database in several places; a couple of them are compound queries where multiple queries are joined by "<dtml-var mysql_delimiter>" values. Many of our queries use this in combination with the "use <database name>" SQL query. The system is using ZODB filestorage (Data.fs) with ZEO and is pretty much out of the box. Has anyone else encountrered a similar problem. Any suggestions as to how to find this bug?