Queries on already established connections hanging for 15min when Redis server disconnected hard

In a test setup with Maxscale and Redis on separate VMs shutting down the Redis service, or even killing the redis-server process the hard way with "kill -9", does not affect Maxscale and its clients that much, queries are just being sent right to a backend server each time without caching.

When powering off the whole Redis VM on the other hand so that the TCP connection to Redis is still open and just inactive from the Maxscale perspective already established client sessions hang on the next query they try to execute until finally running into a timeout.

The same would probably also happen when having a network failure between Maxscale and Redis servers.