如何避免Django单元测试导致MySQL并发中断连接？

Question

我尝试使用以下方法并行运行Django测试：

python manage.py test --keepdb --parallel

但如果测试失败，则会导致SQL连接中止。在MySQL中我可以看到：

^{pr2}$

正因为如此，我在其他测试中不断看到这个错误：

django.db.utils.OperationalError: (2013, "Lost connection to MySQL server at 'reading initial communication packet', system error: 102")

我能做些什么来避免这种情况？以下是其他失败测试的回溯示例：

Using existing test database for alias 'default'...
Traceback (most recent call last):
  File "/Applications/PyCharm.app/Contents/helpers/pycharm/django_test_manage.py", line 157, in <module>
    utility.execute()
  File "/Applications/PyCharm.app/Contents/helpers/pycharm/django_test_manage.py", line 132, in execute
    PycharmTestCommand().run_from_argv(self.argv)
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/core/management/commands/test.py", line 30, in run_from_argv
    super(Command, self).run_from_argv(argv)
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/core/management/base.py", line 348, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/core/management/commands/test.py", line 74, in execute
    super(Command, self).execute(*args, **options)
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/core/management/base.py", line 399, in execute
    output = self.handle(*args, **options)
  File "/Applications/PyCharm.app/Contents/helpers/pycharm/django_test_manage.py", line 97, in handle
    failures = TestRunner(test_labels, **options)
  File "/Applications/PyCharm.app/Contents/helpers/pycharm/django_test_runner.py", line 256, in run_tests
    extra_tests=extra_tests, **options)
  File "/Applications/PyCharm.app/Contents/helpers/pycharm/django_test_runner.py", line 156, in run_tests
    return super(DjangoTeamcityTestRunner, self).run_tests(test_labels, extra_tests, **kwargs)
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/test/runner.py", line 532, in run_tests
    old_config = self.setup_databases()
  File "/Users/dio/code/athena/common/runner.py", line 12, in setup_databases
    result = super(CITestSuiteRunner, self).setup_databases()
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/test/runner.py", line 482, in setup_databases
    self.parallel, **kwargs
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/test/runner.py", line 726, in setup_databases
    serialize=connection.settings_dict.get("TEST", {}).get("SERIALIZE", True),
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/db/backends/base/creation.py", line 56, in create_test_db
    self._create_test_db(verbosity, autoclobber, keepdb)
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/db/backends/base/creation.py", line 165, in _create_test_db
    with self._nodb_connection.cursor() as cursor:
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/db/backends/base/base.py", line 233, in cursor
    cursor = self.make_cursor(self._cursor())
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/db/backends/base/base.py", line 204, in _cursor
    self.ensure_connection()
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/db/backends/base/base.py", line 199, in ensure_connection
    self.connect()
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/db/utils.py", line 95, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/db/backends/base/base.py", line 199, in ensure_connection
    self.connect()
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/db/backends/base/base.py", line 171, in connect
    self.connection = self.get_new_connection(conn_params)
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/django/db/backends/mysql/base.py", line 264, in get_new_connection
    conn = Database.connect(**conn_params)
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/MySQLdb/__init__.py", line 81, in Connect
    return Connection(*args, **kwargs)
  File "/Users/dio/.virtualenvs/athena/lib/python2.7/site-packages/MySQLdb/connections.py", line 193, in __init__
    super(Connection, self).__init__(*args, **kwargs2)
django.db.utils.OperationalError: (2013, "Lost connection to MySQL server at 'reading initial communication packet', system error: 102")