javascript - 蒙哥错误: No More Documents in Tailed Cursor

Question

我有一个上限集合，我正尝试使用 mongoose 对其进行尾部处理。当所有文档都用完或根本没有文档时，tailable 流会出错。

Mongoose 模式

var photoSchema = new Schema({
    name: String,
    operations: Schema.Types.Mixed,
}, {
    capped: {
        size: 300 * 500,
        max: 500,
        autoIndexId: true
    }
});

实现

var RawPhoto = mongoose.model('RawPhoto', photoSchema);
var ProcessedPhoto = mongoose.model('ProcessedPhoto', photoSchema)

var ProcessedPhoto = mongoose.model('ProcessedPhoto', photoSchema)

var processedPhotoStream = ProcessedPhoto.find().tailable(true, 
    {awaitdata: true, numberOfRetries: Number.MAX_VALUE}).stream();

processedPhotoStream.on('data', function(photo){
    console.log(photo.name);
}).on('error', function(error){
    console.error(error);
}).on('close', function(){
    console.log("processed photo stream closed")
});

在我的控制台中，我得到一个 MongoError: No more documents in tailed cursor 和我自己的消息 processed photo stream closed。我看到过去有人因为 mongoose 和最新版本的 MongoDB 不兼容而遇到麻烦，但我仍然遇到这个问题。

Answer 1

您的光标标志不正确，因此被忽略。您真的只需要带有“大写‘D’”的awaitData:

var processedPhotoStream = ProcessedPhoto.find().tailable(true, 
    { awaitData: true }).stream();

addCursorFlag 的 native 驱动程序文档中列出了有效选项

The flag to set, must be one of following ['tailable', 'oplogReplay', 'noCursorTimeout', 'awaitData', 'partial'].

---

没有问题的简单列表

var async = require('async'),
    mongoose = require('mongoose'),
    Schema = mongoose.Schema;

mongoose.connect('mongodb://localhost/capped');
mongoose.set('debug',true);

var photoSchema = new Schema({
  "name": String
}, {
  "capped" : {
    "size": 500 * 1024,
    "max": 500
  }
});

var Photo = mongoose.model('Photo',photoSchema);

var stream = Photo.find().tailable(true,
  { awaitData: true }).stream();

stream.on('data',function(data) {
  console.log(data);
});
stream.on('err',function(err) {
  console.error(err);
});
stream.on('close',function() {
  console.log('done');
});

setInterval(function() {
  Photo.create({ "name": "Ted" },function(err,photo) {

  });
},2000);

不断给予的输出:

Mongoose: photos.find({}) { awaitData: true, tailable: true, fields: undefined }
Mongoose: photos.insert({ name: 'Ted', _id: ObjectId("5715af20daa62598059adaf1"), __v: 0 })
{ __v: 0, name: 'Ted', _id: 5715af20daa62598059adaf1 }
Mongoose: photos.insert({ name: 'Ted', _id: ObjectId("5715af23daa62598059adaf2"), __v: 0 })
{ __v: 0, name: 'Ted', _id: 5715af23daa62598059adaf2 }
Mongoose: photos.insert({ name: 'Ted', _id: ObjectId("5715af25daa62598059adaf3"), __v: 0 })
{ __v: 0, name: 'Ted', _id: 5715af25daa62598059adaf3 }