[Django]-Django + Sqlite: database is locked

From Django doc:

SQLite is meant to be a lightweight database, and thus can’t support a
high level of concurrency. OperationalError: database is locked errors
indicate that your application is experiencing more concurrency than
sqlite can handle in default configuration. This error means that one
thread or process has an exclusive lock on the database connection and
another thread timed out waiting for the lock the be released.

Python’s SQLite wrapper has a default timeout value that determines
how long the second thread is allowed to wait on the lock before it
times out and raises the OperationalError: database is locked error.

If you’re getting this error, you can solve it by:

• Switching to another database backend. At a certain point SQLite becomes too “lite” for real-world applications, and these sorts of
  concurrency errors indicate you’ve reached that point.
• Rewriting your code to reduce concurrency and ensure that database transactions are short-lived.
• Increase the default timeout value by setting the timeout database option