问题
I have a MySQL gone away with Django under WSGI. I found entries for this problem on stackoverflow, but nothing with Django specifically. Google does not help, except for workarounds (like polling the website every once in a while, or increasing the database timeout). Nothing definitive. Technically, Django and/or MySQLdb (I'm using the latest 1.2.3c1) should attempt a reconnect if the server hanged the connection, but this does not happen. How can I solve this issue without workarounds ?
回答1:
show variables like 'wait_timeout';
this is the setting will throw back the "mysql gone away" error
set it to a very large value to prevent it "gone away"
or simple re-ping the mysql connection after certain period
回答2:
Django developers gave one short answer for all questions like this in https://code.djangoproject.com/ticket/21597#comment:29
- Resolution set to wontfix
Actually this is the intended behavior after #15119. See that ticket for the rationale.
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.
回答3:
You could create middleware to ping() the MySQL connection (which will reconnect if it timed out) before processing the view
You could also add middleware to catch the exception, reconnect, and retry the view (I think I would prefer the above solution as simpler, but it should technically work and be performant assuming timeouts are rare. This also assumes a failed view has no side effects, which is a desirable property but can be difficult to do, especially if you write to a filesystem as well as a db in your view.)
来源：https://stackoverflow.com/questions/2582506/2006-mysql-server-has-gone-away-in-wsgi-django