Delete lots of redis keys

gistfile1.js

 var smartDelete = function(clientName, queryKey, cb) {

        var client = redis.getClient(clientName), noneRemaining = false, numDeleted = 0, lastK, duration;

        async.whilst(
          function () { return !noneRemaining; },
          function (callback) {
              
              client.spop(queryKey, function(err, key) {

                 if(key) {      

                  client.del(key,function(err) {
                    
                    numDeleted ++;
                    
                    if(numDeleted === 1) {
                      lastK = new Date();
                    }

                    if(numDeleted % 100000 === 0) {
                      duration = new Date() - lastK;
                      lastK = new Date();
                      logger.silly(clientName + ' deleted ' + numDeleted + ' @ ' + (duration/100) + '/s');
                    }

                    callback(err);

                  });

                 } else {

                  noneRemaining = true;
                  callback();

                 }

              })
          },
          function (err) {
            logger.silly('Deleted from ' + clientName + ': ' + numDeleted);
            cb(err);
          }
        );

    }