message: fetch count faster from db.stats
diff: @@ -414,6 +414,12 @@ export function findAll(model: Mongoose.Model<any>): Q.Promise<any> {
  */
  export function countWhere(model: Mongoose.Model<any>, query: any): Q.Promise<any> {
  + if (Object.keys(query).length == 0) {
  + return Q.nbind(model.collection.stats, model.collection)().then((result: any) => {
  + return Q.resolve(result.count);
  + })
  + }
  +
  let queryObj = model.find(mongooseHelper.setShardCondition(model, query)).count();
  //winstonLog.logInfo(`findWhere query is ${query}`);
  return Q.nbind(queryObj.exec, queryObj)()
  