多任务操作数据库时：2006, 'MySQL server has gone away'

查到Django官网中：https://code.djangoproject.com/ticket/21597

这不是数据库的问题。

If you hit this problem and don't want to understand what's going on, don't reopen this ticket, just do this:

RECOMMENDED SOLUTION: close the connection with 

    from django.db import connection

    connection.close() 

when you know that your program is going to be idle for a long time.

CRAPPY SOLUTION: increase wait_timeout so it's longer than the maximum idle time of your program.

In this context, idle time is the time between two successive database queries.

def main():
    q = Queue()
    p_1 = Process(target=func1, args=(selected, q))
    p_2 = Process(target=func2, args=(request, q))
    p_1.start()
    p_2.start()
    q.put(2)
    return执行过程：
1）main：开启两个进程；往队列q里写入2；return
2）func1 和 func2 开始while循环，
func1先从q中读到2，于是执行func11，
func11之后往q中写3；
func2在1秒后开始从q中读到3，开始执行func22。def func1(dc_id, q=None):
    while 1:
        value = q.get(True)
        time.sleep(1)
        if value == 2:
            func11(dc_id) # 操作数据库
            q.put(3)
            breakdef func2(request, q):
    while 1:
        time.sleep(1)
        value = q.get(True)
        if value == 3:
            func22(request) # 操作数据库
            breakdef func11(dc_id):
    if not is_connection_usable():
        connection.close()
    ...操作数据库...def func22(dc_id):
    if not is_connection_usable():
        connection.close()
    ...操作数据库...from django.db import connection
def is_connection_usable():
    try:
        print 'connection', connection.connection.ping()
    except:
        return False
    else:
        return True