I've been experiencing a performance issue using Edge and it appears to
be related to how Dependencies handles classes that are generated at
runtime. I'll give a simplified scenario of my problem for the sake of
clarity. These are the migrations:
001_create_publications.rb:
class CreatePublications < ActiveRecord::Migration
def self.up
create_table :publications do |t|
t.column :name, :string
t.column :type, :string
end
end
def self.down
drop_table :publications
end
end
These are the current values in the table:
1, 'A Tale of Two Cities', 'Book'
2, '1984', 'Book'
And the models...
app/models/publication.rb:
class Publication < ActiveRecord::Base
end
Now, Book would be a model that is generated at runtime (i.e., it is
not found in a file). While it wouldn't necessarily make sense for
this sort of setup, it does in a plugin like acts_as_versioned that
generates a, for example, Publication::Version class at runtime.
So this is what I'm running in the console:
Loading development environment.
Object.const_set('Book', Class.new(Publication))
=> Book
Book.find(:all)
=> [#<Book:0x5966dd8 @attributes={"name"=>"A Tale of Two Cities",
"type"=>"Book", "id"=>"1"}>, #<Book:0x5965898 @attributes={"name"=>"A
Tale of Three Cities", "type"=>"Book", "id"=>"2"}>]
Book.find(:all)
=> [#<Book:0x5961ff4 @attributes={"name"=>"A Tale of Two Cities",
"type"=>"Book", "id"=>"1"}>, #<Book:0x5960ab4 @attributes={"name"=>"A
Tale of Three Cities", "type"=>"Book", "id"=>"2"}>]
This produces the right results, however a log from the dependencies
shows the following:
Book Columns (0.000000) SHOW FIELDS FROM publications
Book Load (0.016000) SELECT * FROM publications WHERE (
(publications.`type` = 'Book' ) )
Dependencies: called require_or_load("/book", nil)
Dependencies: loading /book
Dependencies: called load_file("/book.rb", [])
Dependencies: called new_constants_in()
Dependencies: called require_or_load("/book", nil)
Dependencies: loading /book
Dependencies: called load_file("/book.rb", [])
Dependencies: called new_constants_in()
Book Load (0.016000) SELECT * FROM publications WHERE (
(publications.`type` = 'Book' ) )
Dependencies: called require_or_load("/book", nil)
Dependencies: loading /book
Dependencies: called load_file("/book.rb", [])
Dependencies: called new_constants_in()
Dependencies: called require_or_load("/book", nil)
Dependencies: loading /book
Dependencies: called load_file("/book.rb", [])
Dependencies: called new_constants_in()
As a result of how things are currently working, it appears as though
it will try to look for a book file every single time an instance of
Book is instantiated, regardless of whether it's looked for it before.
This seems to be what is causing my performance issue.
My question is: Is this behavior expected? That is, should
ActiveRecord classes that are generated at runtime be causing
Dependencies to constantly look for the file?
A first crack at the issue shows that require_association_class in
associations.rb is calling require_association, which in turn will
cause the Dependencies to look for a file named 'book'. This is
regardless of whether the constant already exists. I'm tempted to add
a conditional that only calls require_association if the constant does
not already exist (or even going deeper and having associate_with check
if the constant exists). However, I haven't yet looked into the issues
this could cause with other parts of ActiveRecord.
Thanks to anyone who might have insight into the issue.
However, this is run from the
