I would suggest looking at this implementation: http://appengine-cookbook.appspot.com/recipe/high-concurrency-counters-without-sharding http://appengine-cookboo

I would suggest looking at this implementation: http://appengine-cookbook.appspot.com/recipe/high-concurrency-counters-without-sharding http://appengine-cookbook.appspot.com/recipe/high-concurrenc... My current counter system uses a single datastore entity per counter and uses the new CapabilitySet API to check if memcache will go offline in near future.