PubSub close() causes Connections from a ConnectionPool to disconnect

[levic]

I was wondering why my redis server showed more connect/disconnects than I expected when using PubSub

• I obtain a connection from a ConnectionPool
• I call pubsub = connection.pubsub()
• I do some processing
• I now call pubsub.close()
• This calls reset()
• reset() calls disconnect() before releasing the connection back to the pool
• disconnect() causes the underlying TCP socket to get disconnected
• the next time the connection is handed out from the ConnectionPool it has to reconnect (avoiding this is the main reason for using a ConnectionPool in the first place)

The documentation states:

When you’re finished with a PubSub object, call its .close() method to shutdown the connection.

(and there are various other places that will call it anyway, eg PubSub.__del__, PubSubWorkerThread.run)

There appears to be no other way to release the connection back to the ConnectionPool (and even if you don't call PubSub.close(), PubSub.__del__() will invoke it at some point anyway). Simply commenting out the disconnect() causes other errors, it looks like the "unsubscribe" acknowledgement is not consumed but I only did a quick test.

Is this an oversight or is there some limitation of PubSub that means it must reset the TCP connection?

[vladvildanov]

@levic Hey! Sorry for the late response, the reason why we decided to explicitly close the connection before the release is a client buffer on server-side, Pub/Sub is a long-running thing so buffer is usually quite heavy and to be able to fully close the context of this connection and trigger server to flush a buffer we have to disconnect