Rails: Query comparison between a 3-level nested association.

log.log

  Page Load (0.3ms)  SELECT `pages`.* FROM `pages` 
  ObjectMap Load (0.4ms)  SELECT `object_maps`.* FROM `object_maps` WHERE `object_maps`.`page_id` = 1
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 1
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 2
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 17
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 18
  ObjectMap Load (0.3ms)  SELECT `object_maps`.* FROM `object_maps` WHERE `object_maps`.`page_id` = 3
  ObjectProperty Load (0.2ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 28
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 29
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 30
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 31
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 32
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 45
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 46
  ObjectMap Load (0.3ms)  SELECT `object_maps`.* FROM `object_maps` WHERE `object_maps`.`page_id` = 4
  ObjectProperty Load (0.4ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 33
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 34
  ObjectProperty Load (0.4ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 35
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 36
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 37
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 38
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 39
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 40
  ObjectProperty Load (0.4ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 41
  ObjectProperty Load (0.4ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 42
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 43
  ObjectMap Load (0.3ms)  SELECT `object_maps`.* FROM `object_maps` WHERE `object_maps`.`page_id` = 15
  ObjectProperty Load (0.5ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 44
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 47
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 48
  ObjectProperty Load (0.4ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 49
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 50
  ObjectProperty Load (0.8ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 51
  ObjectMap Load (0.4ms)  SELECT `object_maps`.* FROM `object_maps` WHERE `object_maps`.`page_id` = 19
  ObjectMap Load (0.4ms)  SELECT `object_maps`.* FROM `object_maps` WHERE `object_maps`.`page_id` = 27
  ObjectMap Load (0.4ms)  SELECT `object_maps`.* FROM `object_maps` WHERE `object_maps`.`page_id` = 28
  ObjectProperty Load (0.4ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` = 52
  Rendered layouts/_flash.html.haml (0.1ms)

log_with_includes.log

  Page Load (0.2ms)  SELECT `pages`.* FROM `pages` 
  ObjectMap Load (0.4ms)  SELECT `object_maps`.* FROM `object_maps` WHERE `object_maps`.`page_id` IN (1, 3, 4, 15, 19, 27, 28)
  ObjectProperty Load (0.3ms)  SELECT `object_properties`.* FROM `object_properties` WHERE `object_properties`.`object_map_id` IN (1, 2, 17, 18, 28, 29, 30, 31, 32, 45, 46, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 47, 48, 49, 50, 51, 52)
  Rendered layouts/_flash.html.haml (0.1ms)

nav_builder.rb

#Associations without eager loading cause the first log
Page.all.each do |page|
  #...
  page.object_maps.each do |object_map|
    #...
      object_map.object_properties.each do |object_property|
        #...
      end
  end
end

#Associations with eager loading cause the second log
Page.includes(object_maps: :object_properties).all.each do |page|
  #...
  page.object_maps.each do |object_map|
    #...
      object_map.object_properties.each do |object_property|
        #...
      end
  end
end