Pymongo not automatically connecting to new primary

[Gabe Rives-Corbett]

Hello,

I'm using pymongo/flask with a connection string like this: "mongodb://mongo-1,mongo-2,mongo-3/untapt?replicaSet=myreplicaset".

It all works fine on the initial connection.  If we kill the primary, we see the cluster elect a new one, the pymongo request fails with an AutoReconnect error, but it does not appear to attempt to reconnect to the new primary.  With PyMongo 2.x we get the error: "AutoReconnect: No replica set primary available for query with ReadPreference PRIMARY"

With 3.x the initial connection does not work at all and we get: "ServerSelectionTimeoutError: No replica set members found yet"

Any help would be appreciated.

[Bernie Hackett]

I'm going to guess either your application uses the multiprocessing module to fork subprocesses or your web framework does. Either way, read this:

http://api.mongodb.com/python/current/faq.html#using-pymongo-with-multiprocessing

With the related in-depth technical explanation:

http://api.mongodb.com/python/current/faq.html#pymongo-fork-safe