1119339 - Enable database connection reuse in Django

Status: NEW

(www.mozilla.org :: Bedrock, defect)

Description

[Paul [:pmac] McLanahan]

Django 1.6 comes with the ability to reuse db connections natively (i.e. without a separate connection pooling proxy). We'd like to enable this after we've moved to 1.6.

Comment 1

[Paul [:pmac] McLanahan]

To do this we set CONN_MAX_AGE to some number of seconds. According to the docs[0] this number should be lower than the DB server's idle timeout.

Sheeri, can you tell us what the bedrock cluster's servers settings are for this kind of thing, and/or give us a recommended value for this setting.

[0] https://docs.djangoproject.com/en/1.7/ref/databases/#persistent-database-connections

Comment 2

[Sheeri Cabral [:sheeri]]

The timeout is 600 seconds, or 10 minutes.

CONN_MAX_AGE is the maximum age that a connection is used/reused before django kills it. The problem is that you might build up too many connections if django does not kill a thread, but in this case django is reusing them, so theoretically you won't build up connections, because if you have an idle connection, a "new" connection will just use the idle one.

I would *think* that in that case, setting it to "None" is appropriate - letting the db kill a persistent connection that's idle for longer than the system timeout. 

However, I would test this on staging. That's what it's for. My team is happy to be there while you test, looking at # of database connections and seeing if it goes up drastically during a, say, 15 minute test.

Comment 3

[Paul [:pmac] McLanahan]

Sounds great Sheeri! We'll do that and let you know when we're ready to test.

Thanks!