When I load [[en:Main_page]] and watch memcached GETs using tcpdump, I see Echo making five round-trips to memcached on every page view:
enwiki:echo-notification-count-message:...:1.5 enwiki:echo-notification-count-alert:...:1.5 enwiki:echo-notification-timestamp-message:...:1.5 enwiki:echo-notification-timestamp-alert:...:1.5 enwiki:echo:user:had:messages:...:1.5
It'd be better if these were consolidated into a single getMulti() call. It'd be better still if these values were stored under a single key. And it'd be best of all if they were stored in the session data that is already getting retrieved on every page view.