Hi group!
My question is this: Is there a way to turn of eager loading for a #count
call on a model (ModelLogging.eager_loading = false ??), since that SEEMS to
be my problem (#count doesn't seem to take the :preload option).
The issue I have is with calling count on a Polymorphic model:
class ModelLogging < ActiveRecord::Base
belongs_to :model, :polymorphic => true
end
class PipingClass < ActiveRecord::Base
has_many :model_loggings, :as => :model
end
The model_loggings table looks like:
===============
create_table "model_loggings", :force => true do |t|
t.string "model_type"
t.integer "model_id"
t.string "field_name"
t.string "old_value"
t.string "new_value"
t.datetime "modified_at"
t.integer "employee_id"
t.datetime "created_at"
t.datetime "updated_at"
end
==============
There is only one record in the model_loggings table:
===============
#<ModelLogging id: 1, model_type: "PipingClass", model_id: 3331, field_name:
"class_code", old_value: "BCA", new_value: "A", modified_at: "2009-08-06
11:55:44", employee_id: nil, created_at: "2009-08-06 11:55:44", updated_at:
"2009-08-06 11:55:44">
===============
If I try the following, it works:
===============
> ModelLogging.find(:all, :include => [:model])
=> [#<ModelLogging id: 1, model_type: "PipingClass", model_id: 3331,
field_name: "class_code", old_value: "BCA", new_value: "A", modified_at:
"2009-08-06 11:55:44", employee_id: nil, created_at: "2009-08-06 11:55:44",
updated_at: "2009-08-06 11:55:44">]
> ModelLogging.count
=> 1
===============
But...
===============
> ModelLogging.count(:include => [:model])
=> ActiveRecord::EagerLoadPolymorphicError: Can not eagerly load the
polymorphic association :model
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/associations.rb:1960:in
`initialize'
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/associations.rb:1853:in
`new'
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/associations.rb:1853:in
`build_join_association'
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/associations.rb:1836:in
`build'
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/associations.rb:1839:in
`build'
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/associations.rb:1838:in
`each'
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/associations.rb:1838:in
`build'
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/associations.rb:1758:in
`initialize'
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/calculations.rb:210:in
`new'
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/calculations.rb:210:in
`construct_calculation_sql'
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/calculations.rb:243:in
`execute_simple_calculation'
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/calculations.rb:134:in
`calculate'
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/calculations.rb:130:in
`catch'
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/calculations.rb:130:in
`calculate'
from
/usr/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/calculations.rb:48:in
`count_without_trace_ActiveRecord___self_name__find'
from
/home/telaeris/sandbox/po_tracker_bpcherrypoint/vendor/plugins/newrelic_rpm/lib/new_relic/agent/method_tracer.rb:138:in
`count_without_trace_ActiveRecord_find'
... 55 levels...
from
/usr/local/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/handler/mongrel.rb:61:in
`process'
from
/usr/local/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in
`process_client'
from
/usr/local/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `each'
from
/usr/local/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in
`process_client'
from
/usr/local/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run'
from
/usr/local/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in
`initialize'
from
/usr/local/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new'
from
/usr/local/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run'
from
/usr/local/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in
`initialize'
from
/usr/local/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new'
from
/usr/local/lib/ruby/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `run'
from
/usr/local/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/handler/mongrel.rb:34:in
`run'
from
/home/telaeris/.gem/ruby/1.8/gems/rails-2.3.2/lib/commands/server.rb:111
from /usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in
`gem_original_require'
from /usr/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in
`require'
================
Not sure what to do without diving into AR internals some more, something I
don't really want to do.
I've also found this ticket, but no action has really happened on it. I am
pondering submitting a failing test case for it if I can't think of another
way around this:
https://rails.lighthouseapp.com/projects/8994/tickets/1166-count-works-differently-than-find-with-polymorphic-include
Any thoughts?
PS: I should be at tonight's meeting, and I am pushing to attend the RBBQ,
but I may be fishing for longer than expected that day.
Thanks!
--
Adam Grant
Lead Web Engineer
Telaeris, Inc.
[email protected]
(858) 627-9710
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