问题
In Django, how do I make my code recover from a database connection which is dead ? This is the scenario:
# requests enters view handler
# executes code which does some synchronous tasks without any database interaction for 15min.
# first database activity in this request after 15min.
try:
o, created = act_details.objects.get_or_create(id=1) # this line fails because of a dead database connection.
except Exception as e:
logger.error(e) # ORA-03114: not connected to ORACLE
Assuming I handle the exception, is there a way to put things back on track by creating a new database connection in the exception block ?
My issue is similar to Recover from dead database connection in Django but different because the connections I use are entirely framework managed.
This issue happens only when the remote server/network/firewall drops idle connections.
回答1:
Normally as a developer you shouldn't be exposed to the internals of Django that way.
As Django establishes a connection on each request it has an opportunity to both pool connections and persist connections.
Connections time out eventially anyway so you need a mechanism to provide you with database connections.
A pool pattern is really what you need and depending on your situation there are some packages that offer Connection pooling for Oracle: https://pypi.python.org/pypi/django-oraclepool
I haven't tried that to tell you if it works though.
UPDATE
Alternativelly you can access the underlying database cursor:
from django.db import connections
try:
o, created = act_details.objects.get_or_create(id=1) # this line fails because of a dead database connection.
except Exception as e:
logger.error(e) # ORA-03114: not connected to ORACLE
conn = connections['oracle']
if conn.connection is None: # Attempt to get it again
with connection.cursor() as c:
c.execute("SELECT * from act_details WHERE id = %s" % [self.id])
This way though you lose all the benefits of the Django ORM but its a workaround.
来源：https://stackoverflow.com/questions/30024004/idle-database-connections-in-django