我第一次尝试优化活动记录中的一些 N+1 查询。有 3 个要杀死 - 2 个很容易通过 .includes 调用,但我终其一生都无法弄清楚为什么第三个仍在调用一堆查询。下面的相关代码 - 如果有人有任何建议,我会非常感激。
控制器:
@enquiries = Comment.includes(:children).faqs_for_project(@project)
模型;
def self.faqs_for_project(project)
Comment.for_project_and_enquiries(project, project.enquiries).where(:published => true).order("created_at DESC")
end
(及相关范围)
scope :for_project_and_enquiries, lambda{|p, qs| where('(commentable_type = ? and commentable_id = ?) or (commentable_type = ? and commentable_id IN (?))', "Project", p.id, "Enquiry", qs.collect{|q| q.id})}
看法:
...
= render :partial => 'comments/comment', :collection => @enquries
...
(以及部分中的违规行)
...
= 'Read by ' + pluralize(comment.acknowledgers.count, 'lead')
...
为每个评论调用两个 SQL 查询。2个查询是:
SQL (2.8ms) SELECT COUNT(*) FROM "users" INNER JOIN "acknowledgements" ON "users".id = "acknowledgements".user_id WHERE (("acknowledgements".feedback_type = 'Comment') AND ("acknowledgements".feedback_id = 177621))
CACHE (0.0ms) SELECT "users".* FROM "users" WHERE "users"."id" = 1295 LIMIT 1
我原以为将 (:user, :acknowledgements) 附加到控制器的 .includes 中可以解决问题,但它似乎没有任何效果。如果有人对我所缺少的有任何建议,我将非常感激