Rails排序或排序查询很慢

Question

Using Rails 3.2, Ruby 1.9, will_paginate. I have 100,000 records, and tested the following queries:

# 1000+ms to load
@shops = Shop.where(:shop_type => @type).paginate(:include => :photos, :page => params[:page], :per_page => 25, :order => 'created_at DESC')

# 1000+ms to load
@shops = Shop.paginate(:include => :photos, :page => params[:page], :per_page => 25, :order => 'created_at DESC')

# 1000+ms to load
@shops = Shop.order('created_at DESC').limit(25)

# 1+ms to load
@shops = Shop.paginate(:include => :photos, :page => params[:page], :per_page => 25)

I noticed that the order option is incredibly slow. Test results show that will_paginate is not a problem.

How should I change it so that the query with order can be sped up.

Answer 1

Yes, try to create index on the order column. It will speed it up.