OperationalError：使用 Process 时出现磁盘 I/O 错误

Question

我正在运行一个使用 sqlite3 作为后端的 django 应用程序。我有一个执行数据库写入操作的函数。类似于下面给出的。

def task_run():
    db_write()

这在正常情况下工作正常。我在 Process 模块中调用了相同的函数，它抛出了OperationalError: disk I/O error

p = Process(target=self.task_run, args=())
        p.start()
        p.join()

Error:
Traceback (most recent call last):
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/process.py", line 258, in _bootstrap
    self.run()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/process.py", line 114, in run
    self._target(*self._args, **self._kwargs)
  File "...runner.py", line 277, in task_runner
    getattr(main, "first_function")("some random")
  File "...modules/test/main.py", line 13, in first_function
    self.__event__('information',"Testing plugin profiles")
  File "...rc_plugin.py", line 28, in __event__
    event = Event.objects.post_event(self.job_id, self.task_id, type, message)

  File "...managers.py", line 39, in post_event
    if len(dup_events)>0:
  File "...lib/python2.7/site-packages/django/db/models/query.py", line 144, in __len__
    self._fetch_all()
  File "...lib/python2.7/site-packages/django/db/models/query.py", line 965, in _fetch_all
    self._result_cache = list(self.iterator())
  File "...lib/python2.7/site-packages/django/db/models/query.py", line 238, in iterator
    results = compiler.execute_sql()
  File "...lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 840, in execute_sql
    cursor.execute(sql, params)
  File "...lib/python2.7/site-packages/django/db/backends/utils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
    File "...lib/python2.7/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "...lib/python2.7/site-packages/django/db/utils.py", line 97, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)

  File "...lib/python2.7/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "...lib/python2.7/site-packages/django/db/backends/sqlite3/base.py", line 318, in execute
    return Database.Cursor.execute(self, query, params)
OperationalError: disk I/O error

知道为什么会这样吗？如何使用多处理调用相同的函数？

Answer 1

我今天也遇到了这个使用错误，也许你可以用记忆绕道。如下所示：

con = sqlite3.connect(":memory:")