fix projects sorting; fix Postgresql issue with LIMIT and DISTINCT; fix query performance

app/controllers/dashboard_controller.rb

@@ -5,7 +5,7 @@ class DashboardController < ApplicationController
 
   def index
     @groups = Group.where(id: current_user.projects.pluck(:group_id))
-    @projects = current_user.projects_with_events
+    @projects = current_user.projects_sorted_by_activity
     @projects = @projects.page(params[:page]).per(30)
 
     @events = Event.in_projects(current_user.project_ids)

app/controllers/groups_controller.rb

@@ -54,7 +54,7 @@ class GroupsController < ApplicationController
   end
 
   def projects
-    @projects ||= current_user.projects_with_events.where(group_id: @group.id)
+    @projects ||= current_user.projects_sorted_by_activity.where(group_id: @group.id)
   end
 
   def project_ids

app/roles/account.rb

@@ -67,7 +67,7 @@ module Account
     events = events.recent.limit(1).first
   end
 
-  def projects_with_events
-    projects.includes(:events).order("events.created_at DESC")
+  def projects_sorted_by_activity
+    projects.order("(SELECT max(events.created_at) FROM events WHERE events.project_id = projects.id) DESC")
   end
 end