Logger Entity in App engine
How about keeping a memcache data structure of request info (recorded as they arrive) and then run an every 5 minute (or faster) cron job that crunches the stats on the last 5 minutes of requests from the memcache and just records those stats in the data store for that 5 minute interval. The same (or a different) cron job could then clear the memcache too - so that it doesn't get too big.
Then you can run big-picture analysis based on the aggregate of 5 minute interval stats, which might be more manageable than analyzing hours of 1500req/s data.
Is it viable to have a logger entity in app engine for writing logs? I'll have an app with ~1500req/sec and am thinking about doing it with a taskqueue. Whenever I receive a request, I would create a task and put it in a queue to write something to a log entity (with a date and string properties). 
I need this because I have to put statistics in the site that I think that doing it this way and reading the logs with a backend later would solve the problem. Would rock if I had programmatic access to the app engine logs (from logging), but since that's unavailable, I dont see any other way to do it..  
Feedback is much welcome