[Bug 856004] [NEW] "OperationalError: database is locked" encountered under very light load while using REST API

[Stephen A. Goss]

Public bug reported:

I've seen this error twice while running integration tests (of our own
application) that access Mailman 3 using the API. The load on Mailman is
very light, as all requests made to the API are serial, never in
parallel. Of course the various processing queues in MM3 are separate
processes and could be doing work concurrently.

The platform is Centos 6.

Traceback (most recent call last):
  File "/usr/lib64/python2.6/wsgiref/handlers.py", line 93, in run
    self.result = application(self.environ, self.start_response)
  File "/home/sgoss/mailman_clone/src/mailman/rest/wsgiapp.py", line 63, in __call__
    config.db.commit()
  File "/home/sgoss/mailman_clone/src/mailman/database/stock.py", line 70, in commit
    self.store.commit()
  File "/home/sgoss/phoenix-deploy/lib/python2.6/site-packages/storm-0.18-py2.6-linux-x86_64.egg/storm/store.py", line 122, in commit
    self._connection.commit()
  File "/home/sgoss/phoenix-deploy/lib/python2.6/site-packages/storm-0.18-py2.6-linux-x86_64.egg/storm/databases/sqlite.py", line 126, in commit
    self.raw_execute("COMMIT", _end=True)
  File "/home/sgoss/phoenix-deploy/lib/python2.6/site-packages/storm-0.18-py2.6-linux-x86_64.egg/storm/databases/sqlite.py", line 154, in raw_execute
    return Connection.raw_execute(self, statement, params)
  File "/home/sgoss/phoenix-deploy/lib/python2.6/site-packages/storm-0.18-py2.6-linux-x86_64.egg/storm/database.py", line 321, in raw_execute
    self._check_disconnect(raw_cursor.execute, *args)
  File "/home/sgoss/phoenix-deploy/lib/python2.6/site-packages/storm-0.18-py2.6-linux-x86_64.egg/storm/database.py", line 366, in _check_disconnect
    return function(*args, **kwargs)
OperationalError: database is locked

The backend here is SQLite, which falls over very quickly under
concurrent load. If the goal here is to create a stable mailing list
server, maybe SQLite is a poor default.

** Affects: mailman
     Importance: Undecided
         Status: New


** Tags: mailman3

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Title:
  "OperationalError: database is locked" encountered under very light
  load while using REST API

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