在asp.net和ravendb中处理基于活动的feed的最佳方法

I will have an activity feed per user that displays all activity related to events the user is subscribed to and the feed will pull in the most current 20 or so activities. The way I have it setup is all activity regardless of the event its related to is stored in one collection and the document itself has an "event" property I query against and index. The basic query is just select activities from collection where event is in the users event subscription list ordered by date. I store a hash of the list of the users event subscriptions and cache the results of the query using the hash as the key for xx seconds so if another user is subscribed to same exact events I can pull the results from cache instead, I'm not concerned with results being xx seconds stale.I will have an activity feed per user that disp