Scaling to 1.3 Million Concurrent MQTT Connections on a 12 Core, 32G CentOS server.

New PubSub, Router Design (#402). Prepare for scaling to 10 millions on one cluster.

Improve the gproc_pool usage with a general emqttd_pool_sup

Improve the design of emqttd_pubsub, add a new emqttd_router module

Route aging mechanism to remove the topics that have no subscriptions

Improve the dashboard, mysql, pgsql, stomp, sockjs plugins

Add ‘topics’, ‘subscriptions’ admin commands

Avoid using mnesia table index and mnesia:index_read API to lower CPU usage

Long Delay on Multiple Topic Subscription (#365)

Subscriptions persistence (#344)

emqttd_ctl: ‘subscriptions’ command to force clients to subscribe some topics (#361)

emqttd_sm: spec of lookup_session/1 is not right BUG (#411)

1.3 million concurrent MQTT connections on a 12 Core, 32G CentOS Server, consume about 15G Memory and 200% CPU.