How to force AR belongs_to include option to eager load?

[Adam Akhtar-2]

Hello

I have two classes

class SolarSystem < ActiveRecord::Base
  has_many :fow_ss_entries, :dependent => :delete_all

class FowSsEntry < ActiveRecord::Base
  belongs_to :galaxy
  belongs_to :solar_system
  belongs_to :player

  named_scope :for, Proc.new { |galaxy, player|
    galaxy = galaxy.id if galaxy.is_a? Galaxy
    player = player.id if player.is_a? Player

    {
      :conditions => {:galaxy_id => galaxy, :player_id => player},
      :include => :solar_system
    }
  }

Now the evil thing is, that even thou' :include is specified, it does
nothing. New AR eager loading resorts to doing n+1 sql queries in
FowSsEntry.for(1,1).each { |fse| fse.solar_system }

How do I force it into joining my table, without impacting my SQL
performance?
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[Frederick Cheung-2]

On Nov 2, 10:56 pm, Artūras Šlajus <rails-mailing-l...@...>
wrote:

> Now the evil thing is, that even thou' :include is specified, it does
> nothing. New AR eager loading resorts to doing n+1 sql queries in
> FowSsEntry.for(1,1).each { |fse| fse.solar_system }
>
> How do I force it into joining my table, without impacting my SQL
> performance?

Is the issue the fact that :include does not always trigger a join
based strategy ? What are the actual sql queries you see?

Fred
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[Adam Akhtar-2]

Frederick Cheung wrote:

> On Nov 2, 10:56�pm, Art�ras �lajus <rails-mailing-l...@...>
> wrote:
>
>> Now the evil thing is, that even thou' :include is specified, it does
>> nothing. New AR eager loading resorts to doing n+1 sql queries in
>> FowSsEntry.for(1,1).each { |fse| fse.solar_system }
>>
>> How do I force it into joining my table, without impacting my SQL
>> performance?
>
> Is the issue the fact that :include does not always trigger a join
> based strategy ? What are the actual sql queries you see?

Yes.

I see this:
[2009-11-03 00:35:26|main|debug] FowSsEntry Load (0.0ms)  SELECT * FROM
`fow_ss_entries` WHERE (`fow_ss_entries`.`galaxy_id` = 1 AND
`fow_ss_entries`.`player_id` = 1)
[2009-11-03 00:35:26|main|debug] SolarSystem Load (0.0ms)  SELECT * FROM
`solar_systems` WHERE (`solar_systems`.`id` = 57)
[2009-11-03 00:35:26|main|debug] SolarSystem Load (0.0ms)  SELECT * FROM
`solar_systems` WHERE (`solar_systems`.`id` = 157)
[2009-11-03 00:35:26|main|debug] SolarSystem Load (0.0ms)  SELECT * FROM
`solar_systems` WHERE (`solar_systems`.`id` = 313)
[2009-11-03 00:35:26|main|debug] SolarSystem Load (0.0ms)  SELECT * FROM
`solar_systems` WHERE (`solar_systems`.`id` = 314)

Which is kind of bad ;(

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[chris johnson]

Is there a method for forcing a join-based strategy?

On Nov 3, 2:09 am, Artūras Šlajus <rails-mailing-l...@...>
wrote:

> Frederick Cheung wrote:
> > On Nov 2, 10:56 pm, Art ras lajus <rails-mailing-l...@...>
> > wrote:
>
> >> Now the evil thing is, that even thou' :include is specified, it does
> >> nothing. New AR eager loading resorts to doing n+1 sql queries in
> >> FowSsEntry.for(1,1).each { |fse| fse.solar_system }
>
> >> How do I force it into joining my table, without impacting my SQL
> >> performance?
>
> > Is the issue the fact that :include does not always trigger a join
> > based strategy ? What are the actual sql queries you see?
>
> Yes.
>
> I see this:
> [2009-11-03 00:35:26|main|debug] FowSsEntry Load (0.0ms)  SELECT * FROM
> `fow_ss_entries` WHERE (`fow_ss_entries`.`galaxy_id` = 1 AND
> `fow_ss_entries`.`player_id` = 1)
> [2009-11-03 00:35:26|main|debug] SolarSystem Load (0.0ms)  SELECT * FROM
> `solar_systems` WHERE (`solar_systems`.`id` = 57)
> [2009-11-03 00:35:26|main|debug] SolarSystem Load (0.0ms)  SELECT * FROM
> `solar_systems` WHERE (`solar_systems`.`id` = 157)
> [2009-11-03 00:35:26|main|debug] SolarSystem Load (0.0ms)  SELECT * FROM
> `solar_systems` WHERE (`solar_systems`.`id` = 313)
> [2009-11-03 00:35:26|main|debug] SolarSystem Load (0.0ms)  SELECT * FROM
> `solar_systems` WHERE (`solar_systems`.`id` = 314)
>
> Which is kind of bad ;(
>
> --
> Posted viahttp://www.ruby-forum.com/.

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