apscheduler Lost connection to MySQL server during query
Question: I use apscheduler to execute regular job, and I got some error on it.

"Lost connection to MySQL server during query"

To find the answer, I try some test on it, and found out if my database(MySQL)
"wait_timeout" is less than schedule interval time then this error occur.
(sorry here I made some mistake...is less than...)

in the test:

  * my job setting

scheduler.add_job(period_job, 'interval', minutes=5, id='my_job_id')

  * my database setting

wait_timeout = 60

  * my test code
    
        from apscheduler.schedulers.background import BackgroundScheduler
    from flask import Flask
    app = Flask(__name__)
    
    scheduler = BackgroundScheduler({'apscheduler.jobstores.default': {
            'type': 'sqlalchemy',
            'url': 'mysql+pymysql://user:pass@url:3306/test_apscheduler?charset=utf8'
        },
            'apscheduler.executors.default': {
                'class': 'apscheduler.executors.pool:ThreadPoolExecutor',
                'max_workers': '20'
        },
            'apscheduler.executors.processpool': {
            'type': 'processpool',
            'max_workers': '5'
        },
            'apscheduler.job_defaults.coalesce': 'false',
            'apscheduler.job_defaults.max_instances': '3',
            'apscheduler.timezone': 'UTC',
        })
    
    scheduler.start()
    
    
    @app.route('/')
    def hello_world():
        scheduler.add_job(period_job, 'interval', minutes=5, id='my_job_id')
        return 'Hello World!'
    
    
    def period_job():
        print("hihi")
    
    
    if __name__ == '__main__':
        app.run()
    

total error message:

    
    
    Exception in thread APScheduler:
    Traceback (most recent call last):
      File "C:\Users\skuo\apshcduler\lib\site-packages\sqlalchemy\engine\base.py", line 1139, in _execute_context context)
      File "C:\Users\skuo\apshcduler\lib\site-packages\sqlalchemy\engine\default.py", line 450, in do_execute cursor.execute(statement, parameters)
      File "C:\Users\skuo\apshcduler\lib\site-packages\pymysql\cursors.py", line 158, in execute result = self._query(query)
      File "C:\Users\skuo\apshcduler\lib\site-packages\pymysql\cursors.py", line 308, in _query conn.query(q)
      File "C:\Users\skuo\apshcduler\lib\site-packages\pymysql\connections.py", line 820, in query self._affected_rows = self._read_query_result(unbuffered=unbuffered)
      File "C:\Users\skuo\apshcduler\lib\site-packages\pymysql\connections.py", line 1002, in _read_query_result result.read()
      File "C:\Users\skuo\apshcduler\lib\site-packages\pymysql\connections.py", line 1285, in read first_packet = self.connection._read_packet()
      File "C:\Users\skuo\apshcduler\lib\site-packages\pymysql\connections.py", line 946, in _read_packet packet_header = self._read_bytes(4)
      File "C:\Users\skuo\apshcduler\lib\site-packages\pymysql\connections.py", line 982, in _read_bytes 2013, "Lost connection to MySQL server during query")
    pymysql.err.OperationalError: (2013, 'Lost connection to MySQL server during query')
    
    The above exception was the direct cause of the following exception:
    
    Traceback (most recent call last):
      File "C:\Python34\lib\threading.py", line 921, in _bootstrap_inner self.run()
      File "C:\Python34\lib\threading.py", line 869, in run self._target(*self._args, **self._kwargs)
      File "C:\Users\skuo\apshcduler\lib\site-packages\apscheduler\schedulers\blocking.py", line 27, in _main_loop wait_seconds = self._process_jobs()
      File "C:\Users\skuo\apshcduler\lib\site-packages\apscheduler\schedulers\base.py", line 801, in _process_jobs for job in jobstore.get_due_jobs(now):
      File "C:\Users\skuo\apshcduler\lib\site-packages\apscheduler\jobstores\sqlalchemy.py", line 69, in get_due_jobs return self._get_jobs(self.jobs_t.c.next_run_time <= timestamp)
      File "C:\Users\skuo\apshcduler\lib\site-packages\apscheduler\jobstores\sqlalchemy.py", line 131, in _get_jobs for row in self.engine.execute(selectable):
      File "C:\Users\skuo\apshcduler\lib\site-packages\sqlalchemy\engine\base.py", line 1991, in execute return connection.execute(statement, *multiparams, **params)
      File "C:\Users\skuo\apshcduler\lib\site-packages\sqlalchemy\engine\base.py", line 914, in execute return meth(self, multiparams, params)
      File "C:\Users\skuo\apshcduler\lib\site-packages\sqlalchemy\sql\elements.py", line 323, in _execute_on_connection return connection._execute_clauseelement(self, multiparams, params)
      File "C:\Users\skuo\apshcduler\lib\site-packages\sqlalchemy\engine\base.py", line 1010, in _execute_clauseelement compiled_sql, distilled_params
      File "C:\Users\skuo\apshcduler\lib\site-packages\sqlalchemy\engine\base.py", line 1146, in _execute_context context)
      File "C:\Users\skuo\apshcduler\lib\site-packages\sqlalchemy\engine\base.py", line 1341, in _handle_dbapi_exception exc_info
      File "C:\Users\skuo\apshcduler\lib\site-packages\sqlalchemy\util\compat.py", line 200, in raise_from_cause reraise(type(exception), exception, tb=exc_tb, cause=cause)
      File "C:\Users\skuo\apshcduler\lib\site-packages\sqlalchemy\util\compat.py", line 183, in reraise raise value.with_traceback(tb)
      File "C:\Users\skuo\apshcduler\lib\site-packages\sqlalchemy\engine\base.py", line 1139, in _execute_context context)
      File "C:\Users\skuo\apshcduler\lib\site-packages\sqlalchemy\engine\default.py", line 450, in do_execute cursor.execute(statement, parameters)
      File "C:\Users\skuo\apshcduler\lib\site-packages\pymysql\cursors.py", line 158, in execute result = self._query(query)
      File "C:\Users\skuo\apshcduler\lib\site-packages\pymysql\cursors.py", line 308, in _query conn.query(q)
      File "C:\Users\skuo\apshcduler\lib\site-packages\pymysql\connections.py", line 820, in query self._affected_rows = self._read_query_result(unbuffered=unbuffered)
      File "C:\Users\skuo\apshcduler\lib\site-packages\pymysql\connections.py", line 1002, in _read_query_result result.read()
      File "C:\Users\skuo\apshcduler\lib\site-packages\pymysql\connections.py", line 1285, in read first_packet = self.connection._read_packet()
      File "C:\Users\skuo\apshcduler\lib\site-packages\pymysql\connections.py", line 946, in _read_packet packet_header = self._read_bytes(4)
      File "C:\Users\skuo\apshcduler\lib\site-packages\pymysql\connections.py", line 982, in _read_bytes 2013, "Lost connection to MySQL server during query")
    sqlalchemy.exc.OperationalError: (pymysql.err.OperationalError) (2013, 'Lost connection to MySQL server during query') [SQL: 'SELECT apscheduler_jobs.id, apscheduler_jobs.job_state \nFROM apscheduler_jobs \nWHERE apscheduler_jobs.next_run_time <= %(next_run_time_1)s ORDER BY apscheduler_jobs.next_run_time'] [parameters: {'next_run_time_1': 1457445220.361246}]
    

does anyone know what happened to this? and how to fix it?


Answer: what is the setting of interactive_timeout ?

**wait_timeout:**

Description: Time in seconds that the server waits for a connection to become
active before closing it. The session value is initialized when a thread
starts up from either the global value, if the connection is **non-
interactive** , or from the interactive_timeout value, if the connection is
interactive.

