Dashboard calculations are done with an async job now

app/assets/javascripts/admin/controllers/admin_dashboard_controller.js

@@ -42,5 +42,9 @@ Discourse.AdminDashboardController = Ember.Controller.extend({
 
   problemsTimestamp: function() {
     return moment(this.get('problemsFetchedAt')).format('LLL');
-  }.property('problemsFetchedAt')
+  }.property('problemsFetchedAt'),
+
+  updatedTimestamp: function() {
+    return moment(this.get('updated_at')).format('LLL');
+  }.property('updated_at')
 });

app/assets/javascripts/admin/routes/admin_dashboard_route.js

@@ -14,7 +14,7 @@ Discourse.AdminDashboardRoute = Discourse.Route.extend({
   },
 
   fetchDashboardData: function(c) {
-    if( !c.get('dashboardFetchedAt') || moment().subtract('hour', 1).toDate() > c.get('dashboardFetchedAt') ) {
+    if( !c.get('dashboardFetchedAt') || moment().subtract('minutes', 30).toDate() > c.get('dashboardFetchedAt') ) {
       c.set('dashboardFetchedAt', new Date());
       Discourse.AdminDashboard.find().then(function(d) {
         if( Discourse.SiteSettings.version_checks ){
@@ -32,7 +32,7 @@ Discourse.AdminDashboardRoute = Discourse.Route.extend({
           c.set('top_referrers', topReferrers);
         }
 
-        ['admins', 'moderators', 'blocked', 'banned', 'top_traffic_sources', 'top_referred_topics'].forEach(function(x) {
+        ['admins', 'moderators', 'blocked', 'banned', 'top_traffic_sources', 'top_referred_topics', 'updated_at'].forEach(function(x) {
           c.set(x, d[x]);
         });
 

app/assets/javascripts/admin/templates/dashboard.js.handlebars

@@ -276,3 +276,9 @@
   </div>
 </div>
 <div class='clearfix'></div>
+
+<div class="dashboard-stats pull-right">
+  <div class="pull-right">{{i18n admin.dashboard.last_updated}} {{updatedTimestamp}}</div>
+  <div class='clearfix'></div>
+</div>
+<div class='clearfix'></div>

app/controllers/admin/dashboard_controller.rb

@@ -1,9 +1,6 @@
 class Admin::DashboardController < Admin::AdminController
-
   def index
-    dashboard_data = Rails.cache.fetch("admin-dashboard-data-#{Discourse::VERSION::STRING}", expires_in: 1.hour) do
-      AdminDashboardData.fetch_all.as_json
-    end
+    dashboard_data = AdminDashboardData.fetch_cached_stats || Jobs::DashboardStats.new.execute({})
     dashboard_data.merge!({version_check: DiscourseUpdates.check_version.as_json}) if SiteSetting.version_checks?
     render json: dashboard_data
   end

app/models/admin_dashboard_data.rb

@@ -41,9 +41,17 @@ class AdminDashboardData
       notification_email_check ].compact
   end
 
-  def self.fetch_all
+  def self.fetch_stats
     AdminDashboardData.new
   end
+  def self.fetch_cached_stats
+    # The DashboardStats job is responsible for generating and caching this.
+    stats = $redis.get(stats_cache_key)
+    stats ? JSON.parse(stats) : nil
+  end
+  def self.stats_cache_key
+    'dash-stats'
+  end
 
   def self.fetch_problems
     AdminDashboardData.new.problems
@@ -58,10 +66,16 @@ class AdminDashboardData
       blocked: User.blocked.count,
       top_referrers: IncomingLinksReport.find('top_referrers').as_json,
       top_traffic_sources: IncomingLinksReport.find('top_traffic_sources').as_json,
-      top_referred_topics: IncomingLinksReport.find('top_referred_topics').as_json
+      top_referred_topics: IncomingLinksReport.find('top_referred_topics').as_json,
+      updated_at: Time.zone.now.as_json
     }
   end
 
+  def self.recalculate_interval
+    # Could be configurable, but clockwork + multisite need to support it.
+    30 # minutes
+  end
+
   def rails_env_check
     I18n.t("dashboard.rails_env_warning", env: Rails.env) unless Rails.env == 'production'
   end

app/models/site_setting.rb

@@ -239,6 +239,7 @@ class SiteSetting < ActiveRecord::Base
   setting(:delete_user_max_age, 7)
   setting(:delete_all_posts_max, 10)
 
+
   def self.generate_api_key!
     self.api_key = SecureRandom.hex(32)
   end