I'm not arguing that sum should take a block, I'm showing that there are still lots of cases in which you need an array.
Yes it's bad to sum a column on a lot of objects as they will get loaded into memory. But we need to run sum on methods that are not columns too, and we use this with scopes that cut the number of objects down to a number that are fine to process in memory. On 28/02/2013, at 02:13 , Rafael Mendonça França <rafaelmfra...@gmail.com> wrote: > You are using the wrong method. If you want the query always you call it you > should use #load > > Using #load you will know exactly when the query is done > > #sum with block is not recommended since it will load all the object in > memory. This is why it was deprecated. > > The query method is there. It is called #load now. > > > Rafael Mendonça França > http://twitter.com/rafaelfranca > https://github.com/rafaelfranca > > > On Wed, Feb 27, 2013 at 6:42 AM, Will Bryant <will.bry...@gmail.com> wrote: > Hi guys, > > I don't think that the changes made to the behavior of #all in 4.0 are a very > good idea. > > I can see that you no longer need to call all in as many cases as you did > before - that's fine, just don't call it if you don't want it. But that > doesn't mean you never need it or that people who do need it should not have > it available. > > 1. Yes you can use to_a in many cases, but it behaves differently - for > example if you have an association, to_a will return the cached target if the > association has already been loaded. You absolutely need a way to run an > actual query when you want the latest results. to_a cannot be relied upon to > do this in all cases. > > Note lack of a second query: > > irb(main):006:0> p = Project.first > Project Load (0.2ms) SELECT "projects".* FROM "projects" ORDER BY > "projects"."id" ASC LIMIT 1 > => #<Project id: 1, created_at: "2013-02-27 09:38:49", updated_at: > "2013-02-27 09:38:49"> > irb(main):007:0> p.tasks.to_a > Task Load (0.2ms) SELECT "tasks".* FROM "tasks" WHERE "tasks"."project_id" > = ? [["project_id", 1]] > => [#<Task id: 1, project_id: 1, created_at: "2013-02-27 09:38:52", > updated_at: "2013-02-27 09:38:52">, #<Task id: 2, project_id: 1, created_at: > "2013-02-27 09:38:53", updated_at: "2013-02-27 09:38:53">] > irb(main):008:0> p.tasks.to_a > => [#<Task id: 1, project_id: 1, created_at: "2013-02-27 09:38:52", > updated_at: "2013-02-27 09:38:52">, #<Task id: 2, project_id: 1, created_at: > "2013-02-27 09:38:53", updated_at: "2013-02-27 09:38:53">] > irb(main):010:0> p.tasks.all > DEPRECATION WARNING: Relation#all is deprecated. If you want to eager-load a > relation, you can call #load (e.g. `Post.where(published: true).load`). If > you want to get an array of records from a relation, you can call #to_a (e.g. > `Post.where(published: true).to_a`). (called from irb_binding at (irb):10) > => [#<Task id: 1, project_id: 1, created_at: "2013-02-27 09:38:52", > updated_at: "2013-02-27 09:38:52">, #<Task id: 2, project_id: 1, created_at: > "2013-02-27 09:38:53", updated_at: "2013-02-27 09:38:53">] > irb(main):011:0> p.tasks.all > DEPRECATION WARNING: Relation#all is deprecated. If you want to eager-load a > relation, you can call #load (e.g. `Post.where(published: true).load`). If > you want to get an array of records from a relation, you can call #to_a (e.g. > `Post.where(published: true).to_a`). (called from irb_binding at (irb):11) > => [#<Task id: 1, project_id: 1, created_at: "2013-02-27 09:38:52", > updated_at: "2013-02-27 09:38:52">, #<Task id: 2, project_id: 1, created_at: > "2013-02-27 09:38:53", updated_at: "2013-02-27 09:38:53">] > > 2. It's very important that queries run at the point you think they do in any > application that uses locks or concurrency. Again, if you don't use locks or > concurrency, fine - don't call the query methods. But many people do and > they need to be able to run the queries to make this work. > > 3. It's not true that you no longer need to care whether you have an array or > a relation. For example, methods like sum with a block need arrays, as the > deprecation makes clear: > > irb(main):009:0> p.tasks.sum(&:id) > DEPRECATION WARNING: Calling #sum with a block is deprecated and will be > removed in Rails 4.1. If you want to perform sum calculation over the array > of elements, use `to_a.sum(&block)`. (called from irb_binding at (irb):9) > Task Load (0.1ms) SELECT "tasks".* FROM "tasks" WHERE "tasks"."project_id" > = ? [["project_id", 1]] > => 3 > > 4. It's true that making all basically useless means you can now call all on > a model class itself and get a relation and then you can merge that or > whatever, which was one of the other examples in the changelog. But you > could do that already - using scoped. It is not necessary to break #all's > behavior to get this functionality. > > Have I misunderstood the change? > > If not, can we please put back the query method? Running queries is a pretty > core responsibility of ActiveRecord. > > Thanks, > Will > > -- > You received this message because you are subscribed to the Google Groups > "Ruby on Rails: Core" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to rubyonrails-core+unsubscr...@googlegroups.com. > To post to this group, send email to rubyonrails-core@googlegroups.com. > Visit this group at http://groups.google.com/group/rubyonrails-core?hl=en. > For more options, visit https://groups.google.com/groups/opt_out. > > > > > -- > You received this message because you are subscribed to the Google Groups > "Ruby on Rails: Core" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to rubyonrails-core+unsubscr...@googlegroups.com. > To post to this group, send email to rubyonrails-core@googlegroups.com. > Visit this group at http://groups.google.com/group/rubyonrails-core?hl=en. > For more options, visit https://groups.google.com/groups/opt_out. > > -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Core" group. 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