Issue w/ Eager Loading


#1

Hi,

I have a rails app that uses these models:

class CoreRouter < ActiveRecord::Base
has_many :ports
end

class Port < ActiveRecord::Base
belongs_to :core_router
has_many :addresses
end

class Address < ActiveRecord::Base
belongs_to :port
end

I have one main list page that shows all CoreRouters, the associated
ports and the associated addresses. The problem is that I now have over
400 addresses and I’m seeing over 400 queries when I generate this page,
taking about 10 seconds to load. I thought an answer may be Eager
Loading:

@core_routers = CoreRouter.find(:all, :include => [ :ports, :addresses
])

But that fails:

ActiveRecord::ConfigurationError (Association named ‘addresses’ was not
found; perhaps you misspelled it?):

I’m assuming this is because the CoreRouter class doesn’t have a direct
association with the Address class.

How can I get it to eagerly load the addresses that are associated with
the ports?


#2

has_many :addresses
Loading:
association with the Address class.

How can I get it to eagerly load the addresses that are associated with
the ports?

@core_routers = CoreRouter.find(:all,
:include => {:ports => :addresses})

(it’s either that or…)

:include => :ports => :addresses)

I can never remember as well I’ve never actually done it :slight_smile:


#3

On Jun 12, 2007, at 12:41 PM, Philip H. wrote:

has_many :addresses
page,
was not
@core_routers = CoreRouter.find(:all,
:include => {:ports => :addresses})

(it’s either that or…)

Yeah, it’s that.

and if you need to include a :conditions option when you
have :include’s, you need to indicate the table such as
:conditions => [ ‘core_routers.installed_on < ? AND ports.in_use = ?’,
1.year.ago.beginning_of_day.to_s(:db), true ]

-Rob

Rob B. http://agileconsultingllc.com
removed_email_address@domain.invalid


#4

Philip H. wrote:

@core_routers = CoreRouter.find(:all,
:include => {:ports => :addresses})

That worked great… Dropped my DB time down from about 2 seconds to
less than .5 seconds…


#5

Rob B. wrote:

and if you need to include a :conditions option when you
have :include’s, you need to indicate the table such as
:conditions => [ ‘core_routers.installed_on < ? AND ports.in_use = ?’,
1.year.ago.beginning_of_day.to_s(:db), true ]

Thanks Rob - I don’t need this yet, but might!