Mongoose doesn't execute all on data

I try since five hours to create a distance search with an precreated collection of cached cities in MongoDB with NodeJs + Mongoose. The data comes from opengeodb and fits fine in the collection, but when I try to process the data from my collection it seems some documents where not processed. I use the following to process it:

var citySchema = new Schema({
 postalcode: String,
 cityname: String,
 state: String,
 stateshort: String,
 fiftykm: [String],
 lat: Number,
 lon: Number,
});
var city = mongoose.mdel('city', citySchema);




city.findOne({}).stream()
 .on('error', function(err){
   if(err) throw err;
  })
 .on('data', function(doc){
   var tmp = doc.toObject();
   city.findOne({postalcode : {$ne: tmp.postalcode}}).stream()
   .on('error', function(err){ if(err) throw err;})
   .on('data', function(compdoc){
     var comptmp = compdoc.toObject();
     if(distanz(tmp.lat, tmp.lon, comptmp.lat, comptmp.lon) < 50){
      city.update({_id: tmp._id}, {$push: {fiftykm: comptmp.postalcode}},function(err, model){
       if(err) throw err;
       console.log(model);
      });
     }
    });
   })
 .on('end', function(){
  console.log('all done');
 });

my tries debugging this with console.log() and tee, grep shows to me that some documents where not be called. I hope you can help me... or give me some other solution to do this at all 16480 documents

Thanks in advance!