diff --git a/app/assets/javascripts/ci/build.coffee b/app/assets/javascripts/ci/build.coffee
index 7afe8bf79e2..fca0c3bae5c 100644
--- a/app/assets/javascripts/ci/build.coffee
+++ b/app/assets/javascripts/ci/build.coffee
@@ -1,9 +1,12 @@
 class CiBuild
   @interval: null
+  @state: null
 
-  constructor: (build_url, build_status) ->
+  constructor: (build_url, build_status, build_state) ->
     clearInterval(CiBuild.interval)
 
+    @state = build_state
+
     @initScrollButtonAffix()
 
     if build_status == "running" || build_status == "pending"
@@ -26,14 +29,18 @@ class CiBuild
       CiBuild.interval = setInterval =>
         if window.location.href.split("#").first() is build_url
           $.ajax
-            url: build_url
+            url: build_url + "/trace.json?state=" + encodeURIComponent(@state)
             dataType: "json"
-            success: (build) =>
-              if build.status == "running"
-                $('#build-trace code').html build.trace_html
-                $('#build-trace code').append '<i class="fa fa-refresh fa-spin"/>'
+            success: (log) =>
+              @state = log.state
+              if log.status is "running"
+                if log.append
+                  $('.fa-refresh').before log.html
+                else
+                  $('#build-trace code').html log.html
+                  $('#build-trace code').append '<i class="fa fa-refresh fa-spin"/>'
                 @checkAutoscroll()
-              else if build.status != build_status
+              else if log.status isnt build_status
                 Turbolinks.visit build_url
       , 4000
 
diff --git a/app/controllers/projects/builds_controller.rb b/app/controllers/projects/builds_controller.rb
index 3c9a52a5ddd..bb1f6c5e980 100644
--- a/app/controllers/projects/builds_controller.rb
+++ b/app/controllers/projects/builds_controller.rb
@@ -41,7 +41,7 @@ class Projects::BuildsController < Projects::ApplicationController
   def trace
     respond_to do |format|
       format.json do
-        render json: @build.trace_with_state(params_state).merge!(id: @build.id, status: @build.status)
+        render json: @build.trace_with_state(params[:state]).merge!(id: @build.id, status: @build.status)
       end
     end
   end
@@ -80,13 +80,6 @@ class Projects::BuildsController < Projects::ApplicationController
 
   private
 
-  def params_state
-    begin
-      JSON.parse(params[:state], symbolize_names: true)
-    rescue
-    end
-  end
-
   def build
     @build ||= project.builds.unscoped.find_by!(id: params[:id])
   end
diff --git a/app/views/projects/builds/show.html.haml b/app/views/projects/builds/show.html.haml
index 0da0477bdd0..c7b9c36a3ab 100644
--- a/app/views/projects/builds/show.html.haml
+++ b/app/views/projects/builds/show.html.haml
@@ -1,6 +1,6 @@
 - page_title "#{@build.name} (##{@build.id})", "Builds"
 = render "header_title"
-- trace = build.trace_for_state
+- trace_with_state = @build.trace_with_state
 
 .build-page
   .row-content-block.top-block
@@ -86,7 +86,7 @@
         %pre.trace#build-trace
           %code.bash
             = preserve do
-              = raw trace[:html]
+              = raw trace_with_state[:html]
               - if @build.active?
                 %i{:class => "fa fa-refresh fa-spin"}
 
@@ -219,4 +219,4 @@
 
 
   :javascript
-    new CiBuild("#{namespace_project_build_url(@project.namespace, @project, @build)}", "#{@build.status}", "#{trace[:state]}")
+    new CiBuild("#{namespace_project_build_url(@project.namespace, @project, @build)}", "#{@build.status}", "#{trace_with_state[:state]}")
diff --git a/lib/ci/ansi2html.rb b/lib/ci/ansi2html.rb
index d29e68570ff..5fed43aaebd 100644
--- a/lib/ci/ansi2html.rb
+++ b/lib/ci/ansi2html.rb
@@ -90,7 +90,7 @@ module Ci
 
       def convert(raw, new_state)
         reset_state
-        restore_state(new_state) if new_state && new_state[:offset].to_i < raw.length
+        restore_state(raw, new_state) if new_state
 
         start = @offset
         ansi = raw[@offset..-1]
@@ -187,15 +187,20 @@ module Ci
       end
 
       def state
-        STATE_PARAMS.inject({}) do |h, param|
+        state = STATE_PARAMS.inject({}) do |h, param|
           h[param] = send(param)
           h
         end
+        Base64.urlsafe_encode64(state.to_json)
       end
 
-      def restore_state(new_state)
+      def restore_state(raw, new_state)
+        state = Base64.urlsafe_decode64(new_state)
+        state = JSON.parse(state, symbolize_names: true)
+        return if state[:offset].to_i > raw.length
+
         STATE_PARAMS.each do |param|
-          send("#{param}=".to_sym, new_state[param])
+          send("#{param}=".to_sym, state[param])
         end
       end