How does one get a count of rows in a Datastore model in Google App Engine?

Question

I need to get a count of records for a particular model on App Engine. How does one do it?

I bulk uploaded more than 4000 records but modelname.count() only shows me

Answer 1

You should use Datastore Statistics:

Query query = new Query("__Stat_Kind__");
query.addFilter("kind_name", FilterOperator.EQUAL, kind);       
Entity entityStat = datastore.prepare(query).asSingleEntity();
Long totalEntities = (Long) entityStat.getProperty("count");

Please note that the above does not work on the development Datastore but it works in production (when published).

I see that this is an old post, but I'm adding an answer in benefit of others searching for the same thing.