# Default Homebrew MySQL server config
[mysqld]
# Only allow connections from localhost
bind-address = 127.0.0.1
wait_timeout = 10
interactive_timeout = 10

➜  ~ brew services restart mysql
Stopping `mysql`... (might take a while)
==> Successfully stopped `mysql` (label: homebrew.mxcl.mysql)
==> Successfully started `mysql` (label: homebrew.mxcl.mysql)
 

mysql> show variables like '%wait_timeout%';
+--------------------------+----------+
| Variable_name            | Value    |
+--------------------------+----------+
| innodb_lock_wait_timeout | 50       |
| lock_wait_timeout | 31536000 |
| wait_timeout | 10 |
+--------------------------+----------+
3 rows in set (0.00 sec)

>>> XXX.objects.exists()
True
>>> import time
>>> time.sleep(15)
>>> XXX.objects.exists()
True
>>> XXX.objects.exists()
...
django.db.utils.OperationalError: (2013, 'Lost connection to MySQL server during query')
>>> XXX.objects.exists()
...
django.db.utils.OperationalError: (2006, 'MySQL server has gone away')

>>> Alarm.objects.exists()
True
>>> from django.db import connection
>>> connection.close()
>>> time.sleep(10)
>>> Alarm.objects.exists()
True
>>>

DATABASES = {
	'default': {
		'ENGINE': 'django.db.backends.mysql',
 'CONN_MAX_AGE': 5,
 <other params here>
 }
}

# Register an event to reset transaction state and close connections past
# their lifetime.
def close_old_connections(**kwargs):
 for conn in connections.all():
 conn.close_if_unusable_or_obsolete()


signals.request_started.connect(close_old_connections)
signals.request_finished.connect(close_old_connections)

from django.db import connections


# ref: django.db.close_old_connections
def close_old_connections():
 for conn in connections.all():
 conn.close_if_unusable_or_obsolete()


def handle_db_connections(func):
 def func_wrapper(request):
 close_old_connections()
 result = func(request)
 close_old_connections()

 return result

 return func_wrapper

# ------割-------
@handle_db_connections
def process_trsbrain_request(request):
 ...