优化SQL查询：1，members与users表关联查询； 2，blogs表单查询

app/controllers/users_controller.rb

@@ -1250,7 +1250,12 @@ class UsersController < ApplicationController
       end
     else
       #  @user_activities = UserActivity.where("(container_type = 'Project' and container_id in #{user_project_ids} and act_type in #{project_types}) or (container_type = 'Course' and container_id in #{user_course_ids} and act_type in #{course_types})or (container_type = 'Principal' and act_type= '#{principal_types}' and container_id = #{@user.id})").order('updated_at desc').limit(10).offset(@page * 10)
-      blog_ids = "("+@user.blog.id.to_s+","+((User.watched_by(@user.id).count == 0 )? '0' :User.watched_by(@user.id).map{|u| u.blog.id}.join(','))+")"
+      # blog_ids = "("+@user.blog.id.to_s+","+((User.watched_by(@user.id).count == 0 )? '0' :User.watched_by(@user.id).map{|u| u.blog.id}.join(','))+")"
+      # 减少数据库交互
+      user_ids = "(" + @user.id.to_s + "," + User.watched_by(@user.id).map{|u| u.id }.join(',') + ")"
+      watched_user_blog_ids = Blog.select("id").where("author_id in #{user_ids}").map { |blog| blog.id}.join(",")
+      blog_ids = "(" + watched_user_blog_ids + ")"
+
       @user_activities = UserActivity.where("(container_type = 'Project' and container_id in #{user_project_ids} and act_type in #{project_types})" +
                                                 "or (container_type = 'Course' and container_id in #{user_course_ids} and act_type in #{course_types}) "+
                                                 "or (container_type = 'Principal' and act_type= '#{principal_types}' and container_id = #{@user.id}) " +

app/helpers/issues_helper.rb

@@ -111,9 +111,9 @@ module IssuesHelper
 
   def principals_options_for_isuue_list(project)
     if User.current.member_of?(project)
-      project.members.order("lower(users.login)").map{|c| [c.name, c.user_id]}.unshift(["<< #{l(:label_me)} >>", User.current.id]).unshift(["指派给", 0])
+      project.members.includes(:user).order("lower(users.login)").map{|c| [c.name, c.user_id]}.unshift(["<< #{l(:label_me)} >>", User.current.id]).unshift(["指派给", 0])
     else
-      project.members.order("lower(users.login)").map{|c| [c.name, c.user_id]}.unshift(["指派给", 0])
+      project.members.includes(:user).order("lower(users.login)").map{|c| [c.name, c.user_id]}.unshift(["指派给", 0])
     end
   end