Sharding Counters - Google App Engine - Google Code

Sharding Counters - Google App Engine - Google Code: "When you want to know the value of the counter you read all of the counter shards and add them all together. The more shards you have the higher the throughput you will have for increments on your counter. This technique works for a lot more than just counters and an important skill to learn is spotting the entities in your application with a lot of writes and then finding good ways to shard them."