diff --git a/app.js b/app.js
index e2c09a04..36e63b86 100644
--- a/app.js
+++ b/app.js
@@ -299,6 +299,9 @@ function handleTermSignals () {
       })
     }
   }, 100)
+  setTimeout(() => {
+    process.exit(1)
+  }, 5000)
 }
 process.on('SIGINT', handleTermSignals)
 process.on('SIGTERM', handleTermSignals)
diff --git a/lib/processQueue.js b/lib/processQueue.js
index d47b1fc2..d98c4139 100644
--- a/lib/processQueue.js
+++ b/lib/processQueue.js
@@ -7,11 +7,20 @@ const EventEmitter = require('events').EventEmitter
  */
 
 const QueueEvent = {
-  Tick: 'Tick'
+  Tick: 'Tick',
+  Push: 'Push',
+  Finish: 'Finish'
 }
 
 class ProcessQueue extends EventEmitter {
-  constructor (maximumLength, triggerTimeInterval = 10) {
+  constructor ({
+    maximumLength = 500,
+    triggerTimeInterval = 5000,
+    // execute on push
+    proactiveMode = true,
+    // execute next work on finish
+    continuousMode = true
+  }) {
     super()
     this.max = maximumLength
     this.triggerTime = triggerTimeInterval
@@ -19,12 +28,20 @@ class ProcessQueue extends EventEmitter {
     this.queue = []
     this.lock = false
 
-    this.on(QueueEvent.Tick, () => {
-      if (this.lock) return
-      this.lock = true
-      setImmediate(() => {
-        this.process()
-      })
+    this.on(QueueEvent.Tick, this.onEventProcessFunc.bind(this))
+    if (proactiveMode) {
+      this.on(QueueEvent.Push, this.onEventProcessFunc.bind(this))
+    }
+    if (continuousMode) {
+      this.on(QueueEvent.Finish, this.onEventProcessFunc.bind(this))
+    }
+  }
+
+  onEventProcessFunc () {
+    if (this.lock) return
+    this.lock = true
+    setImmediate(() => {
+      this.process()
     })
   }
 
@@ -62,7 +79,7 @@ class ProcessQueue extends EventEmitter {
     this.taskMap.set(id, true)
     this.queue.push(task)
     this.start()
-    this.emit(QueueEvent.Tick)
+    this.emit(QueueEvent.Push)
     return true
   }
 
@@ -79,7 +96,7 @@ class ProcessQueue extends EventEmitter {
     const finishTask = () => {
       this.lock = false
       setImmediate(() => {
-        this.emit(QueueEvent.Tick)
+        this.emit(QueueEvent.Finish)
       })
     }
     task.processingFunc().then(finishTask).catch(finishTask)
diff --git a/lib/realtime.js b/lib/realtime.js
index 4c2c87bc..a4e77784 100644
--- a/lib/realtime.js
+++ b/lib/realtime.js
@@ -38,7 +38,8 @@ const realtime = {
   maintenance: true
 }
 
-const disconnectProcessQueue = new ProcessQueue(2000, 500)
+const connectProcessQueue = new ProcessQueue({})
+const disconnectProcessQueue = new ProcessQueue({})
 const updateDirtyNoteJob = new UpdateDirtyNoteJob(realtime)
 const cleanDanglingUserJob = new CleanDanglingUserJob(realtime)
 const saveRevisionJob = new SaveRevisionJob(realtime)
@@ -97,6 +98,46 @@ function emitCheck (note) {
 var users = {}
 var notes = {}
 
+function getNotePool () {
+  return notes
+}
+
+function isNoteExistsInPool (noteId) {
+  return !!notes[noteId]
+}
+
+function addNote (note) {
+  if (exports.isNoteExistsInPool(note.id)) return false
+  notes[note.id] = note
+  return true
+}
+
+function getNotePoolSize () {
+  return Object.keys(notes).length
+}
+
+function deleteNoteFromPool(noteId) {
+  delete notes[noteId]
+}
+
+function deleteAllNoteFromPool() {
+  Object.keys(notes).forEach(noteId => {
+    delete notes[noteId]
+  })
+}
+
+function getNoteFromNotePool (noteId) {
+  return notes[noteId]
+}
+
+function getUserPool () {
+  return users
+}
+
+function getUserFromUserPool (userId) {
+  return users[userId]
+}
+
 disconnectProcessQueue.start()
 updateDirtyNoteJob.start()
 cleanDanglingUserJob.start()
@@ -265,7 +306,8 @@ function getStatus (callback) {
 function isReady () {
   return realtime.io &&
     Object.keys(notes).length === 0 && Object.keys(users).length === 0 &&
-    connectionSocketQueue.length === 0 && !isConnectionBusy &&
+    !isConnectionBusy &&
+    connectProcessQueue.queue.length === 0 && !connectProcessQueue.lock &&
     disconnectProcessQueue.queue.length === 0 && !disconnectProcessQueue.lock
 }
 
@@ -327,6 +369,15 @@ function parseNoteIdFromSocket (socket, callback) {
   })
 }
 
+function parseNoteIdFromSocketAsync (socket) {
+  return new Promise((resolve, reject) => {
+    parseNoteIdFromSocket(socket, (err, id) => {
+      if (err) return reject(err)
+      resolve(id)
+    })
+  })
+}
+
 // TODO: test it
 function emitOnlineUsers (socket) {
   var noteId = socket.noteId
@@ -374,48 +425,6 @@ function emitRefresh (socket) {
   socket.emit('refresh', out)
 }
 
-// TODO: test it
-function isDuplicatedInSocketQueue (queue, socket) {
-  for (var i = 0; i < queue.length; i++) {
-    if (queue[i] && queue[i].id === socket.id) {
-      return true
-    }
-  }
-  return false
-}
-
-// TODO: test it
-function clearSocketQueue (queue, socket) {
-  for (var i = 0; i < queue.length; i++) {
-    if (!queue[i] || queue[i].id === socket.id) {
-      queue.splice(i, 1)
-      i--
-    }
-  }
-}
-
-// TODO: test it
-function connectNextSocket () {
-  setTimeout(function () {
-    isConnectionBusy = false
-    if (connectionSocketQueue.length > 0) {
-      startConnection(connectionSocketQueue[0])
-    }
-  }, 1)
-}
-
-// TODO: test it
-function interruptConnection (socket, noteId, socketId) {
-  if (notes[noteId]) delete notes[noteId]
-  if (users[socketId]) delete users[socketId]
-  if (socket) {
-    clearSocketQueue(connectionSocketQueue, socket)
-  } else {
-    connectionSocketQueue.shift()
-  }
-  connectNextSocket()
-}
-
 function checkViewPermission (req, note) {
   if (note.permission === 'private') {
     if (req.user && req.user.logged_in && req.user.id === note.owner) {
@@ -435,65 +444,14 @@ function checkViewPermission (req, note) {
 }
 
 var isConnectionBusy = false
-var connectionSocketQueue = []
 
 // TODO: test it
-function finishConnection (socket, noteId, socketId) {
-  // if no valid info provided will drop the client
-  if (!socket || !notes[noteId] || !users[socketId]) {
-    return interruptConnection(socket, noteId, socketId)
-  }
-  // check view permission
-  if (!checkViewPermission(socket.request, notes[noteId])) {
-    interruptConnection(socket, noteId, socketId)
-    return failConnection(403, 'connection forbidden', socket)
-  }
-  let note = notes[noteId]
-  let user = users[socketId]
-  // update user color to author color
-  if (note.authors[user.userid]) {
-    user.color = users[socket.id].color = note.authors[user.userid].color
-  }
-  note.users[socket.id] = user
-  note.socks.push(socket)
-  note.server.addClient(socket)
-  note.server.setName(socket, user.name)
-  note.server.setColor(socket, user.color)
-
-  // update user note history
-  updateHistory(user.userid, note)
-
-  emitOnlineUsers(socket)
-  emitRefresh(socket)
-
-  // clear finished socket in queue
-  clearSocketQueue(connectionSocketQueue, socket)
-  // seek for next socket
-  connectNextSocket()
-
-  if (config.debug) {
-    let noteId = socket.noteId
-    logger.info('SERVER connected a client to [' + noteId + ']:')
-    logger.info(JSON.stringify(user))
-    // logger.info(notes);
-    getStatus(function (data) {
-      logger.info(JSON.stringify(data))
-    })
-  }
-}
-
-// TODO: test it
-function startConnection (socket) {
-  if (isConnectionBusy) return
-  isConnectionBusy = true
-
-  var noteId = socket.noteId
-  if (!noteId) {
-    return failConnection(404, 'note id not found', socket)
-  }
-
-  if (!notes[noteId]) {
-    var include = [{
+async function fetchFullNoteAsync (noteId) {
+  return models.Note.findOne({
+    where: {
+      id: noteId
+    },
+    include: [{
       model: models.User,
       as: 'owner'
     }, {
@@ -507,75 +465,51 @@ function startConnection (socket) {
         as: 'user'
       }]
     }]
+  })
+}
 
-    models.Note.findOne({
-      where: {
-        id: noteId
-      },
-      include: include
-    }).then(function (note) {
-      if (!note) {
-        return failConnection(404, 'note not found', socket)
+function buildAuthorProfilesFromNote (noteAuthors) {
+  const authors = {}
+  noteAuthors.forEach((author) => {
+    const profile = models.User.getProfile(author.user)
+    if (profile) {
+      authors[author.userId] = {
+        userid: author.userId,
+        color: author.color,
+        photo: profile.photo,
+        name: profile.name
       }
-      var owner = note.ownerId
-      var ownerprofile = note.owner ? models.User.getProfile(note.owner) : null
+    }
+  })
+  return authors
+}
 
-      var lastchangeuser = note.lastchangeuserId
-      var lastchangeuserprofile = note.lastchangeuser ? models.User.getProfile(note.lastchangeuser) : null
+function makeNewServerNote (note) {
+  const authors = buildAuthorProfilesFromNote(note.authors)
 
-      var body = note.content
-      var createtime = note.createdAt
-      var updatetime = note.lastchangeAt
-      var server = new ot.EditorSocketIOServer(body, [], noteId, ifMayEdit, operationCallback)
-
-      var authors = {}
-      for (var i = 0; i < note.authors.length; i++) {
-        var author = note.authors[i]
-        var profile = models.User.getProfile(author.user)
-        if (profile) {
-          authors[author.userId] = {
-            userid: author.userId,
-            color: author.color,
-            photo: profile.photo,
-            name: profile.name
-          }
-        }
-      }
-
-      notes[noteId] = {
-        id: noteId,
-        alias: note.alias,
-        title: note.title,
-        owner: owner,
-        ownerprofile: ownerprofile,
-        permission: note.permission,
-        lastchangeuser: lastchangeuser,
-        lastchangeuserprofile: lastchangeuserprofile,
-        socks: [],
-        users: {},
-        tempUsers: {},
-        createtime: moment(createtime).valueOf(),
-        updatetime: moment(updatetime).valueOf(),
-        server: server,
-        authors: authors,
-        authorship: note.authorship
-      }
-
-      return finishConnection(socket, noteId, socket.id)
-    }).catch(function (err) {
-      return failConnection(500, err, socket)
-    })
-  } else {
-    return finishConnection(socket, noteId, socket.id)
+  return {
+    id: note.id,
+    alias: note.alias,
+    title: note.title,
+    owner: note.ownerId,
+    ownerprofile: note.owner ? models.User.getProfile(note.owner) : null,
+    permission: note.permission,
+    lastchangeuser: note.lastchangeuserId,
+    lastchangeuserprofile: note.lastchangeuser ? models.User.getProfile(note.lastchangeuser) : null,
+    socks: [],
+    users: {},
+    tempUsers: {},
+    createtime: moment(note.createdAt).valueOf(),
+    updatetime: moment(note.lastchangeAt).valueOf(),
+    server: new ot.EditorSocketIOServer(note.content, [], note.id, ifMayEdit, operationCallback),
+    authors: authors,
+    authorship: note.authorship
   }
 }
 
 // TODO: test it
 function failConnection (code, err, socket) {
   logger.error(err)
-  // clear error socket in queue
-  clearSocketQueue(connectionSocketQueue, socket)
-  connectNextSocket()
   // emit error info
   socket.emit('info', {
     code: code
@@ -655,7 +589,7 @@ function updateUserData (socket, user) {
   }
 }
 
-function canEditNote(notePermission, noteOwnerId, currentUserId) {
+function canEditNote (notePermission, noteOwnerId, currentUserId) {
   switch (notePermission) {
     case 'freely':
       return true
@@ -736,85 +670,137 @@ function updateHistory (userId, note, time) {
   if (note.server) history.updateHistory(userId, noteId, note.server.document, time)
 }
 
-function getUserPool () {
-  return users
+function getUniqueColorPerNote(noteId, maxAttempt = 10) {
+  // random color
+  let color = randomcolor()
+  if (!notes[noteId]) return color
+
+  const maxrandomcount = maxAttempt
+  let randomAttemp = 0
+  let found = false
+  do {
+    Object.keys(notes[noteId].users).forEach(userId => {
+      if (notes[noteId].users[userId].color === color) {
+        found = true
+      }
+    });
+    if (found) {
+      color = randomcolor()
+      randomAttemp++
+    }
+  } while (found && randomAttemp < maxrandomcount)
+  return color
 }
 
-function getUserFromUserPool (userId) {
-  return users[userId]
-}
+function queueForConnect (socket) {
+  connectProcessQueue.push(socket.id, async function () {
+    try {
+      const noteId = await exports.parseNoteIdFromSocketAsync(socket)
+      if (!noteId) {
+        return exports.failConnection(404, 'note id not found', socket)
+      }
+      // store noteId in this socket session
+      socket.noteId = noteId
+      // initialize user data
+      // random color
+      var color = getUniqueColorPerNote(noteId)
+      // create user data
+      users[socket.id] = {
+        id: socket.id,
+        address: socket.handshake.headers['x-forwarded-for'] || socket.handshake.address,
+        'user-agent': socket.handshake.headers['user-agent'],
+        color: color,
+        cursor: null,
+        login: false,
+        userid: null,
+        name: null,
+        idle: false,
+        type: null
+      }
+      exports.updateUserData(socket, users[socket.id])
+      try {
+        if (!isNoteExistsInPool(noteId)) {
+          const note = await fetchFullNoteAsync(noteId)
+          if (!note) {
+            logger.error('note not found')
+            // emit error info
+            socket.emit('info', {
+              code: 404
+            })
+            return socket.disconnect(true)
+          }
+          getNotePool()[noteId] = makeNewServerNote(note)
+        }
+        // if no valid info provided will drop the client
+        if (!socket || !notes[noteId] || !users[socket.id]) {
+          if (notes[noteId]) delete notes[noteId]
+          if (users[socket.id]) delete users[socket.id]
+          return
+        }
+        // check view permission
+        if (!exports.checkViewPermission(socket.request, notes[noteId])) {
+          if (notes[noteId]) delete notes[noteId]
+          if (users[socket.id]) delete users[socket.id]
+          logger.error('connection forbidden')
+          // emit error info
+          socket.emit('info', {
+            code: 403
+          })
+          return socket.disconnect(true)
+        }
+        let note = notes[noteId]
+        let user = users[socket.id]
+        // update user color to author color
+        if (note.authors[user.userid]) {
+          user.color = users[socket.id].color = note.authors[user.userid].color
+        }
+        note.users[socket.id] = user
+        note.socks.push(socket)
+        note.server.addClient(socket)
+        note.server.setName(socket, user.name)
+        note.server.setColor(socket, user.color)
 
-function getNotePool () {
-  return notes
-}
+        // update user note history
+        exports.updateHistory(user.userid, note)
 
-function getNoteFromNotePool (noteId) {
-  return notes[noteId]
-}
+        exports.emitOnlineUsers(socket)
+        exports.emitRefresh(socket)
 
-// TODO: test it
-function connection (socket) {
-  if (realtime.maintenance) return
-  exports.parseNoteIdFromSocket(socket, function (err, noteId) {
-    if (err) {
+        const socketClient = new RealtimeClientConnection(socket)
+        socketClient.registerEventHandler()
+
+        if (config.debug) {
+          let noteId = socket.noteId
+          logger.info('SERVER connected a client to [' + noteId + ']:')
+          logger.info(JSON.stringify(user))
+          // logger.info(notes);
+          getStatus(function (data) {
+            logger.info(JSON.stringify(data))
+          })
+        }
+      } catch (err) {
+        logger.error(err)
+        // emit error info
+        socket.emit('info', {
+          code: 500
+        })
+        return socket.disconnect(true)
+      }
+    } catch (err) {
       return exports.failConnection(500, err, socket)
     }
-    if (!noteId) {
-      return exports.failConnection(404, 'note id not found', socket)
-    }
-
-    if (isDuplicatedInSocketQueue(connectionSocketQueue, socket)) return
-
-    // store noteId in this socket session
-    socket.noteId = noteId
-
-    // initialize user data
-    // random color
-    var color = randomcolor()
-    // make sure color not duplicated or reach max random count
-    if (notes[noteId]) {
-      var randomcount = 0
-      var maxrandomcount = 10
-      var found = false
-      do {
-        Object.keys(notes[noteId].users).forEach(function (userId) {
-          if (notes[noteId].users[userId].color === color) {
-            found = true
-          }
-        })
-        if (found) {
-          color = randomcolor()
-          randomcount++
-        }
-      } while (found && randomcount < maxrandomcount)
-    }
-    // create user data
-    users[socket.id] = {
-      id: socket.id,
-      address: socket.handshake.headers['x-forwarded-for'] || socket.handshake.address,
-      'user-agent': socket.handshake.headers['user-agent'],
-      color: color,
-      cursor: null,
-      login: false,
-      userid: null,
-      name: null,
-      idle: false,
-      type: null
-    }
-    exports.updateUserData(socket, users[socket.id])
-
-    // start connection
-    connectionSocketQueue.push(socket)
-    exports.startConnection(socket)
   })
+}
 
-  const socketClient = new RealtimeClientConnection(socket)
-  socketClient.registerEventHandler()
+function connection (socket) {
+  if (realtime.maintenance) return
+  queueForConnect(socket)
 }
 
 // TODO: test it
 function terminate () {
   disconnectProcessQueue.stop()
+  connectProcessQueue.stop()
   updateDirtyNoteJob.stop()
 }
 
@@ -823,25 +809,31 @@ exports.extractNoteIdFromSocket = extractNoteIdFromSocket
 exports.parseNoteIdFromSocket = parseNoteIdFromSocket
 exports.updateNote = updateNote
 exports.failConnection = failConnection
-exports.isDuplicatedInSocketQueue = isDuplicatedInSocketQueue
 exports.updateUserData = updateUserData
-exports.startConnection = startConnection
 exports.emitRefresh = emitRefresh
 exports.emitUserStatus = emitUserStatus
 exports.emitOnlineUsers = emitOnlineUsers
 exports.checkViewPermission = checkViewPermission
-exports.getNoteFromNotePool = getNoteFromNotePool
 exports.getUserFromUserPool = getUserFromUserPool
 exports.buildUserOutData = buildUserOutData
-exports.getNotePool = getNotePool
 exports.emitCheck = emitCheck
 exports.disconnectSocketOnNote = disconnectSocketOnNote
 exports.queueForDisconnect = queueForDisconnect
 exports.terminate = terminate
-exports.getUserPool = getUserPool
 exports.updateHistory = updateHistory
 exports.ifMayEdit = ifMayEdit
+exports.parseNoteIdFromSocketAsync = parseNoteIdFromSocketAsync
 exports.disconnectProcessQueue = disconnectProcessQueue
-exports.notes = notes
 exports.users = users
+exports.getUserPool = getUserPool
+
+exports.notes = notes
+exports.getNotePool = getNotePool
+exports.getNotePoolSize = getNotePoolSize
+exports.isNoteExistsInPool = isNoteExistsInPool
+exports.addNote = addNote
+exports.getNoteFromNotePool = getNoteFromNotePool
+exports.deleteNoteFromPool = deleteNoteFromPool
+exports.deleteAllNoteFromPool = deleteAllNoteFromPool
+
 exports.saveRevisionJob = saveRevisionJob
diff --git a/test/connectionQueue.test.js b/test/connectionQueue.test.js
index ea2e627d..5b4246f2 100644
--- a/test/connectionQueue.test.js
+++ b/test/connectionQueue.test.js
@@ -22,7 +22,7 @@ describe('ProcessQueue', function () {
   })
 
   it('should not accept more than maximum task', () => {
-    const queue = new ProcessQueue(2)
+    const queue = new ProcessQueue({ maximumLength: 2 })
     const task = {
       id: 1,
       processingFunc: async () => {
@@ -36,7 +36,7 @@ describe('ProcessQueue', function () {
 
   it('should run task every interval', (done) => {
     const runningClock = []
-    const queue = new ProcessQueue(2)
+    const queue = new ProcessQueue({ maximumLength: 2 })
     const task = async () => {
       runningClock.push(clock.now)
     }
@@ -62,7 +62,7 @@ describe('ProcessQueue', function () {
   })
 
   it('should not crash when repeat stop queue', () => {
-    const queue = new ProcessQueue(2, 10)
+    const queue = new ProcessQueue({ maximumLength: 2, triggerTimeInterval: 10 })
     try {
       queue.stop()
       queue.stop()
@@ -74,7 +74,7 @@ describe('ProcessQueue', function () {
   })
 
   it('should run process when queue is empty', (done) => {
-    const queue = new ProcessQueue(2, 100)
+    const queue = new ProcessQueue({ maximumLength: 2, triggerTimeInterval: 100 })
     const processSpy = sinon.spy(queue, 'process')
     queue.start()
     clock.tick(100)
@@ -85,7 +85,7 @@ describe('ProcessQueue', function () {
   })
 
   it('should run process although error occurred', (done) => {
-    const queue = new ProcessQueue(2, 100)
+    const queue = new ProcessQueue({ maximumLength: 2, triggerTimeInterval: 100 })
     const failedTask = sinon.spy(async () => {
       throw new Error('error')
     })
@@ -107,7 +107,7 @@ describe('ProcessQueue', function () {
   })
 
   it('should ignore trigger when event not complete', (done) => {
-    const queue = new ProcessQueue(2, 10)
+    const queue = new ProcessQueue({ maximumLength: 2, triggerTimeInterval: 10 })
     const processSpy = sinon.spy(queue, 'process')
     const longTask = async () => {
       return new Promise((resolve) => {
diff --git a/test/realtime/connection.test.js b/test/realtime/connection.test.js
new file mode 100644
index 00000000..50b6d618
--- /dev/null
+++ b/test/realtime/connection.test.js
@@ -0,0 +1,193 @@
+/* eslint-env node, mocha */
+'use strict'
+
+const assert = require('assert')
+const mock = require('mock-require')
+const sinon = require('sinon')
+
+const { createFakeLogger } = require('../testDoubles/loggerFake')
+const { removeLibModuleCache, makeMockSocket } = require('./utils')
+const realtimeJobStub = require('../testDoubles/realtimeJobStub')
+
+describe('realtime#connection', function () {
+  describe('connection', function () {
+    let realtime
+    let modelStub
+
+    beforeEach(() => {
+      removeLibModuleCache()
+      modelStub = {
+        Note: {
+          findOne: sinon.stub()
+        },
+        User: {},
+        Author: {}
+      }
+      mock('../../lib/logger', createFakeLogger())
+      mock('../../lib/history', {})
+      mock('../../lib/models', modelStub)
+      mock('../../lib/config', {})
+      mock('../../lib/realtimeUpdateDirtyNoteJob', realtimeJobStub)
+      mock('../../lib/realtimeCleanDanglingUserJob', realtimeJobStub)
+      mock('../../lib/realtimeSaveRevisionJob', realtimeJobStub)
+      mock('../../lib/ot', require('../testDoubles/otFake'))
+      realtime = require('../../lib/realtime')
+    })
+
+    afterEach(() => {
+      mock.stopAll()
+      sinon.restore()
+    })
+
+    describe('fail', function () {
+      it('should fast return when server not start', () => {
+        const mockSocket = makeMockSocket()
+        realtime.maintenance = true
+        const spy = sinon.spy(realtime, 'parseNoteIdFromSocket')
+        realtime.connection(mockSocket)
+        assert(!spy.called)
+      })
+
+      it('should failed when parse noteId occur error', (done) => {
+        const mockSocket = makeMockSocket()
+        realtime.maintenance = false
+        const parseNoteIdFromSocketSpy = sinon.stub(realtime, 'parseNoteIdFromSocketAsync').callsFake(async (socket) => {
+          /* eslint-disable-next-line */
+          throw 'error'
+        })
+
+        const failConnectionSpy = sinon.stub(realtime, 'failConnection')
+
+        realtime.connection(mockSocket)
+
+        setTimeout(() => {
+          assert(parseNoteIdFromSocketSpy.called)
+          assert(failConnectionSpy.calledOnce)
+          assert.deepStrictEqual(failConnectionSpy.lastCall.args, [500, 'error', mockSocket])
+          done()
+        }, 50)
+      })
+
+      it('should failed when noteId not exists', (done) => {
+        const mockSocket = makeMockSocket()
+        realtime.maintenance = false
+        const parseNoteIdFromSocketSpy = sinon.stub(realtime, 'parseNoteIdFromSocketAsync').callsFake(async (socket) => {
+          return null
+        })
+
+        const failConnectionSpy = sinon.stub(realtime, 'failConnection')
+
+        realtime.connection(mockSocket)
+
+        setTimeout(() => {
+          assert(parseNoteIdFromSocketSpy.called)
+          assert(failConnectionSpy.calledOnce)
+          assert.deepStrictEqual(failConnectionSpy.lastCall.args, [404, 'note id not found', mockSocket])
+          done()
+        }, 50)
+      })
+    })
+
+    it('should success connect', function (done) {
+      const mockSocket = makeMockSocket()
+      const noteId = 'note123'
+      realtime.maintenance = false
+      const parseNoteIdFromSocketSpy = sinon.stub(realtime, 'parseNoteIdFromSocketAsync').callsFake(async (socket) => {
+        return noteId
+      })
+      const updateUserDataStub = sinon.stub(realtime, 'updateUserData')
+
+      realtime.connection(mockSocket)
+
+      setTimeout(() => {
+        assert.ok(parseNoteIdFromSocketSpy.calledOnce)
+        assert(updateUserDataStub.calledOnce)
+        done()
+      }, 50)
+    })
+
+    describe('flow', function () {
+      it('should establish connection', function (done) {
+        const noteId = 'note123'
+        const mockSocket = makeMockSocket(null, {
+          noteId: noteId
+        })
+        mockSocket.request.user.logged_in = true
+        mockSocket.request.user.id = 'user1'
+        mockSocket.noteId = noteId
+        realtime.maintenance = false
+        sinon.stub(realtime, 'parseNoteIdFromSocketAsync').callsFake(async (socket) => {
+          return noteId
+        })
+        const updateHistoryStub = sinon.stub(realtime, 'updateHistory')
+        const emitOnlineUsersStub = sinon.stub(realtime, 'emitOnlineUsers')
+        const emitRefreshStub = sinon.stub(realtime, 'emitRefresh')
+        const failConnectionSpy = sinon.spy(realtime, 'failConnection')
+
+        let note = {
+          id: noteId,
+          authors: [
+            {
+              userId: 'user1',
+              color: 'red',
+              user: {
+                id: 'user1',
+                name: 'Alice'
+              }
+            },
+            {
+              userId: 'user2',
+              color: 'blue',
+              user: {
+                id: 'user2',
+                name: 'Bob'
+              }
+            }
+          ]
+        }
+        modelStub.Note.findOne.returns(Promise.resolve(note))
+        modelStub.User.getProfile = sinon.stub().callsFake((user) => {
+          return user
+        })
+        sinon.stub(realtime, 'checkViewPermission').returns(true)
+        realtime.connection(mockSocket)
+        setTimeout(() => {
+          assert(modelStub.Note.findOne.calledOnce)
+          assert.deepStrictEqual(modelStub.Note.findOne.lastCall.args[0].include, [
+            {
+              model: modelStub.User,
+              as: 'owner'
+            }, {
+              model: modelStub.User,
+              as: 'lastchangeuser'
+            }, {
+              model: modelStub.Author,
+              as: 'authors',
+              include: [{
+                model: modelStub.User,
+                as: 'user'
+              }]
+            }
+          ])
+          assert(modelStub.Note.findOne.lastCall.args[0].where.id === noteId)
+          assert(updateHistoryStub.calledOnce)
+          assert(emitOnlineUsersStub.calledOnce)
+          assert(emitRefreshStub.calledOnce)
+          assert(failConnectionSpy.callCount === 0)
+          assert(realtime.getNotePool()[noteId].id === noteId)
+          assert(realtime.getNotePool()[noteId].socks.length === 1)
+          assert.deepStrictEqual(realtime.getNotePool()[noteId].authors, {
+            user1: {
+              userid: 'user1', color: 'red', photo: undefined, name: 'Alice'
+            },
+            user2: {
+              userid: 'user2', color: 'blue', photo: undefined, name: 'Bob'
+            }
+          })
+          assert(Object.keys(realtime.getNotePool()[noteId].users).length === 1)
+          done()
+        }, 50)
+      })
+    })
+  })
+})
diff --git a/test/realtime/dirtyNoteUpdate.test.js b/test/realtime/dirtyNoteUpdate.test.js
index 7bb029d9..a3dea190 100644
--- a/test/realtime/dirtyNoteUpdate.test.js
+++ b/test/realtime/dirtyNoteUpdate.test.js
@@ -4,13 +4,14 @@
 const assert = require('assert')
 const mock = require('mock-require')
 const sinon = require('sinon')
-const { removeModuleFromRequireCache, makeMockSocket } = require('./utils')
+const { removeModuleFromRequireCache, makeMockSocket, removeLibModuleCache } = require('./utils')
 
 describe('realtime#update note is dirty timer', function () {
   let realtime
   let clock
 
   beforeEach(() => {
+    removeLibModuleCache()
     clock = sinon.useFakeTimers({
       toFake: ['setInterval']
     })
@@ -69,7 +70,7 @@ describe('realtime#update note is dirty timer', function () {
     setTimeout(() => {
       assert(note2.server.isDirty === false)
       done()
-    }, 5)
+    }, 10)
   })
 
   it('should not do anything when note missing', function (done) {
diff --git a/test/realtime/realtime.test.js b/test/realtime/realtime.test.js
index 903c9a42..4c6d7f74 100644
--- a/test/realtime/realtime.test.js
+++ b/test/realtime/realtime.test.js
@@ -37,96 +37,6 @@ function removeModuleFromRequireCache (modulePath) {
 }
 
 describe('realtime', function () {
-  describe('connection', function () {
-    let realtime
-    beforeEach(() => {
-      mock('../../lib/logger', {
-        error: () => {
-        }
-      })
-      mock('../../lib/history', {})
-      mock('../../lib/models', {
-        Note: {
-          parseNoteTitle: (data) => (data)
-        }
-      })
-      mock('../../lib/config', {})
-      realtime = require('../../lib/realtime')
-    })
-
-    afterEach(() => {
-      removeModuleFromRequireCache('../../lib/realtime')
-      mock.stopAll()
-      sinon.restore()
-    })
-
-    describe('fail', function () {
-      it('should fast return when server not start', () => {
-        const mockSocket = makeMockSocket()
-        realtime.maintenance = true
-        const spy = sinon.spy(realtime, 'parseNoteIdFromSocket')
-        realtime.connection(mockSocket)
-        assert(!spy.called)
-      })
-
-      it('should failed when parse noteId occur error', () => {
-        const mockSocket = makeMockSocket()
-        realtime.maintenance = false
-        const parseNoteIdFromSocketSpy = sinon.stub(realtime, 'parseNoteIdFromSocket').callsFake((socket, callback) => {
-          /* eslint-disable-next-line */
-          callback('error', null)
-        })
-
-        const failConnectionSpy = sinon.stub(realtime, 'failConnection')
-
-        realtime.connection(mockSocket)
-
-        assert(parseNoteIdFromSocketSpy.called)
-        assert(failConnectionSpy.calledOnce)
-        assert.deepStrictEqual(failConnectionSpy.lastCall.args, [500, 'error', mockSocket])
-      })
-
-      it('should failed when noteId not exists', () => {
-        const mockSocket = makeMockSocket()
-        realtime.maintenance = false
-        const parseNoteIdFromSocketSpy = sinon.stub(realtime, 'parseNoteIdFromSocket').callsFake((socket, callback) => {
-          /* eslint-disable-next-line */
-          callback(null, null)
-        })
-
-        const failConnectionSpy = sinon.stub(realtime, 'failConnection')
-
-        realtime.connection(mockSocket)
-
-        assert(parseNoteIdFromSocketSpy.called)
-        assert(failConnectionSpy.calledOnce)
-        assert.deepStrictEqual(failConnectionSpy.lastCall.args, [404, 'note id not found', mockSocket])
-      })
-    })
-
-    it('should success connect', function () {
-      const mockSocket = makeMockSocket()
-      const noteId = 'note123'
-      realtime.maintenance = false
-      const parseNoteIdFromSocketSpy = sinon.stub(realtime, 'parseNoteIdFromSocket').callsFake((socket, callback) => {
-        /* eslint-disable-next-line */
-        callback(null, noteId)
-      })
-      const failConnectionStub = sinon.stub(realtime, 'failConnection')
-      const updateUserDataStub = sinon.stub(realtime, 'updateUserData')
-      const startConnectionStub = sinon.stub(realtime, 'startConnection')
-
-      realtime.connection(mockSocket)
-
-      assert.ok(parseNoteIdFromSocketSpy.calledOnce)
-
-      assert(failConnectionStub.called === false)
-      assert(updateUserDataStub.calledOnce)
-      assert(startConnectionStub.calledOnce)
-      assert(mockSocket.on.callCount === 11)
-    })
-  })
-
   describe('checkViewPermission', function () {
     // role -> guest, loggedInUser, loggedInOwner
     const viewPermission = {
diff --git a/test/realtime/socket-events.test.js b/test/realtime/socket-events.test.js
index dae78dcc..60cfc730 100644
--- a/test/realtime/socket-events.test.js
+++ b/test/realtime/socket-events.test.js
@@ -9,6 +9,27 @@ const { makeMockSocket, removeModuleFromRequireCache } = require('./utils')
 
 describe('realtime#socket event', function () {
   const noteId = 'note123'
+  const note = {
+    id: noteId,
+    authors: [
+      {
+        userId: 'user1',
+        color: 'red',
+        user: {
+          id: 'user1',
+          name: 'Alice'
+        }
+      },
+      {
+        userId: 'user2',
+        color: 'blue',
+        user: {
+          id: 'user2',
+          name: 'Bob'
+        }
+      }
+    ]
+  }
   let realtime
   let clientSocket
   let modelsMock
@@ -16,7 +37,7 @@ describe('realtime#socket event', function () {
   let configMock
   let clock
 
-  beforeEach(function () {
+  beforeEach(function (done) {
     clock = sinon.useFakeTimers({
       toFake: ['setInterval']
     })
@@ -25,9 +46,14 @@ describe('realtime#socket event', function () {
       Note: {
         parseNoteTitle: (data) => (data),
         destroy: sinon.stub().returns(Promise.resolve(1)),
-        update: sinon.stub().returns(Promise.resolve(1))
-      }
+        update: sinon.stub().returns(Promise.resolve(1)),
+        findOne: sinon.stub().returns(Promise.resolve(note))
+      },
+      User: {}
     }
+    modelsMock.User.getProfile = sinon.stub().callsFake((user) => {
+      return user
+    })
     configMock = {
       fullversion: '1.5.0',
       minimumCompatibleVersion: '1.0.0'
@@ -41,27 +67,50 @@ describe('realtime#socket event', function () {
     mock('../../lib/history', {})
     mock('../../lib/models', modelsMock)
     mock('../../lib/config', configMock)
+    mock('../../lib/ot', require('../testDoubles/otFake'))
     realtime = require('../../lib/realtime')
 
     // get all socket event handler
-    clientSocket = makeMockSocket()
+    clientSocket = makeMockSocket(null, {
+      noteId: noteId
+    })
+    clientSocket.request.user.logged_in = true
+    clientSocket.request.user.id = 'user1'
+    // clientSocket.noteId = noteId
     clientSocket.on = function (event, func) {
       eventFuncMap.set(event, func)
     }
     realtime.maintenance = false
-    sinon.stub(realtime, 'parseNoteIdFromSocket').callsFake((socket, callback) => {
-      /* eslint-disable-next-line */
-      callback(null, noteId)
-    })
+
+    realtime.io = (function () {
+      const roomMap = new Map()
+      return {
+        to: function (roomId) {
+          if (!roomMap.has(roomId)) {
+            roomMap.set(roomId, {
+              emit: sinon.stub()
+            })
+          }
+          return roomMap.get(roomId)
+        }
+      }
+    }())
+
     const wrappedFuncs = []
-    wrappedFuncs.push(sinon.stub(realtime, 'failConnection'))
     wrappedFuncs.push(sinon.stub(realtime, 'updateUserData'))
-    wrappedFuncs.push(sinon.stub(realtime, 'startConnection'))
+    wrappedFuncs.push(sinon.stub(realtime, 'emitOnlineUsers'))
+    wrappedFuncs.push(sinon.stub(realtime, 'parseNoteIdFromSocketAsync').returns(Promise.resolve(noteId)))
+    wrappedFuncs.push(sinon.stub(realtime, 'updateHistory'))
+    wrappedFuncs.push(sinon.stub(realtime, 'emitRefresh'))
+
     realtime.connection(clientSocket)
 
-    wrappedFuncs.forEach((wrappedFunc) => {
-      wrappedFunc.restore()
-    })
+    setTimeout(() => {
+      wrappedFuncs.forEach((wrappedFunc) => {
+        wrappedFunc.restore()
+      })
+      done()
+    }, 50)
   })
 
   afterEach(function () {
@@ -70,6 +119,7 @@ describe('realtime#socket event', function () {
     mock.stopAll()
     sinon.restore()
     clock.restore()
+    clientSocket = null
   })
 
   describe('refresh', function () {
@@ -126,7 +176,7 @@ describe('realtime#socket event', function () {
     it('should not call emitUserStatus when note not exists', () => {
       const userStatusFunc = eventFuncMap.get('user status')
       const emitUserStatusStub = sinon.stub(realtime, 'emitUserStatus')
-      realtime.notes = {}
+      realtime.deleteAllNoteFromPool()
       realtime.users[clientSocket.id] = {}
       const userData = {
         idle: true,
@@ -232,6 +282,7 @@ describe('realtime#socket event', function () {
 
     it('should not return user list when note not exists', function () {
       const onlineUsersFunc = eventFuncMap.get('online users')
+      realtime.deleteAllNoteFromPool()
       onlineUsersFunc()
       assert(clientSocket.emit.called === false)
     })
@@ -256,12 +307,13 @@ describe('realtime#socket event', function () {
       const userChangedFunc = eventFuncMap.get('user changed')
       const updateUserDataStub = sinon.stub(realtime, 'updateUserData')
       const emitOnlineUsersStub = sinon.stub(realtime, 'emitOnlineUsers')
+      realtime.deleteAllNoteFromPool()
       userChangedFunc()
       assert(updateUserDataStub.called === false)
       assert(emitOnlineUsersStub.called === false)
     })
 
-    it('should direct return when note not exists', function () {
+    it('should direct return when note\'s users not exists', function () {
       const userChangedFunc = eventFuncMap.get('user changed')
       realtime.notes[noteId] = {
         users: {}
@@ -414,29 +466,28 @@ describe('realtime#socket event', function () {
         }
       }
 
-      realtime.notes[noteId] = {
+      realtime.deleteAllNoteFromPool()
+      realtime.addNote({
+        id: noteId,
         owner: ownerId
-      }
-
-      realtime.io = {
-        to: function () {
-          return {
-            emit: sinon.stub()
-          }
-        }
-      }
+      })
 
       checkViewPermissionSpy = sinon.spy(realtime, 'checkViewPermission')
       permissionFunc = eventFuncMap.get('permission')
     })
 
     it('should disconnect when lose view permission', function (done) {
-      realtime.notes[noteId].permission = 'editable'
-      realtime.notes[noteId].socks = [clientSocket, undefined, otherClient]
+      realtime.getNoteFromNotePool(noteId).permission = 'editable'
+      realtime.getNoteFromNotePool(noteId).socks = [clientSocket, undefined, otherClient]
 
       permissionFunc('private')
 
       setTimeout(() => {
+        // should change note permission to private
+        assert(modelsMock.Note.update.calledOnce)
+        assert(modelsMock.Note.update.lastCall.args[0].permission === 'private')
+        assert(modelsMock.Note.update.lastCall.args[1].where.id === noteId)
+        // should check all connected client
         assert(checkViewPermissionSpy.callCount === 2)
         assert(otherClient.emit.calledOnce)
         assert(otherClient.disconnect.calledOnce)
diff --git a/test/testDoubles/otFake.js b/test/testDoubles/otFake.js
new file mode 100644
index 00000000..9fd5d3fd
--- /dev/null
+++ b/test/testDoubles/otFake.js
@@ -0,0 +1,18 @@
+'use strict'
+
+const sinon = require('sinon')
+
+class EditorSocketIOServerFake {
+  constructor () {
+    this.addClient = sinon.stub()
+    this.onOperation = sinon.stub()
+    this.onGetOperations = sinon.stub()
+    this.updateSelection = sinon.stub()
+    this.setName = sinon.stub()
+    this.setColor = sinon.stub()
+    this.getClient = sinon.stub()
+    this.onDisconnect = sinon.stub()
+  }
+}
+
+exports.EditorSocketIOServer = EditorSocketIOServerFake