Google App Engine counters

For all my data in the GAE Datastore I have a model for keeping track of counters/total number of records (since we can't use traditional SUM queries). I want to know the most efficient way of incrementing these global count values whenever I insert/delete a record. This is what I'm currently doing:

counter = DBCounter.all().fetch(1)
dbc = DBCounter(totalTopics=counter[0].totalTopics+1)
dbc.put()

 But this seems quite sloppy to me. Any thoughts on a better way to do this?

Answer:

If you need to keep scalability while counting, you should look into Joe Gregorio's article on sharding counters and DocSavage's implementation of the idea.
AppEngineFan's excellent blog also has info on scalable non-sharded counters, see this one which uses task queues and points to the previous article on using cron jobs instead.