Ahh, I get it. So it's not *really* eager-loading, just grouping the queries by commentable_type. Like I said before: I'm fine if someone wants to swap in will_paginate for paginating_find as long as the upgrade is transparent (meaning people who upgrade don't have to do any work). Thanks! Bruno
On Mon, Oct 5, 2009 at 12:21 PM, moritz <[email protected]> wrote: > > Without going through the code magic, it doesn't do one single select > nor a join, but groups the selects per commentable_type per page, > which would still be a saving in my opinion compared to one select > call per comment record. > > >> Comment.paginate(:all, :include => :commentable, :page => 1, :per_page > => 5) > Comment Load (0.6ms) SELECT * FROM "comments" LIMIT 5 OFFSET 0 > Article Load (0.8ms) SELECT * FROM "articles" WHERE > ("articles"."id" IN (1,2)) > Photo Load (0.2ms) SELECT * FROM "photos" WHERE ("photos"."id" = > 1) > > On Oct 5, 8:10 am, Bruno Bornsztein <[email protected]> > wrote: > > I'm pretty confused by that. How does will_paginate know which tables to > > join on? Every row in the comments table could be associated with a > > different kind of commentable. Unless I'm missing something, there's no > way > > that select can be done in one query. Example: > > Comments Table > > ID commentable_type > > 1 Post > > 2 User > > 3 Clipping > > 4 User > > 5 Post > > > > How can you eagerly load the commentable association? You'd have to do a > > join on posts, users, and clippings, without knowing in advance which > tables > > you need to join on. > > > > The only thing I can think of is that will_paginate grabs the result set > and > > loops through it and loads the association for each row. Anybody else > know > > how this is working? > > > > On Mon, Oct 5, 2009 at 10:04 AM, moritz <[email protected]> wrote: > > > > > will_paginate seems to be handling it: > > > > > >> Comment.paginate(:all, :include => :commentable, :page => 1, > :per_page > > > => 2) > > > Comment Load (0.4ms) SELECT * FROM "comments" LIMIT 2 OFFSET 0 > > > Article Load (0.2ms) SELECT * FROM "articles" WHERE > > > ("articles"."id" = 1) > > > Photo Load (0.3ms) SELECT * FROM "photos" WHERE ("photos"."id" = > > > 1) > > > > > >> Comment.paginate(:all, :include => :commentable, :page => 2, > :per_page > > > => 2) > > > Comment Load (0.4ms) SELECT * FROM "comments" LIMIT 2 OFFSET 2 > > > Article Load (0.8ms) SELECT * FROM "articles" WHERE > > > ("articles"."id" IN (1,2)) > > > > > compared with: > > > >> Comment.paginate(:all, :page => 1, :per_page => 2) > > > Comment Load (0.4ms) SELECT * FROM "comments" LIMIT 2 OFFSET 0 > > > SQL (0.2ms) SELECT count(*) AS count_all FROM "comments" > > > > > This definitely reduces the amount of database queries issued in a > > > longer list. > > > > > On Oct 5, 7:50 am, Bruno Bornsztein <[email protected]> > > > wrote: > > > > Hmmm.... strange that will_paginate doesn't raise an error. It should > > > *not* be > > > > able to eager load a polymorphic association like commentable. The > > > problem > > > > is that with a polymorphic association, the commentable could be from > any > > > > number of tables (it could be a User, a Post, a Clipping, etc.), so > eager > > > > loading won't work because Rails doesn't know which tables to join on > > > ahead > > > > of time. > > > > I suspect something else is going on here, like maybe will_paginate > just > > > > disregards the :include parameter when it's polymorphic (or > something). > > > > > > I'm not strongly opposed to using will_paginate if the integration is > > > clean > > > > and upgrading is smooth, but I don't see any great benefit in moving > to > > > it > > > > (maybe someone can convince me). > > > > > > Thanks, > > > > Bruno > > > > > > On Sun, Oct 4, 2009 at 10:35 PM, moritz <[email protected]> wrote: > > > > > > > I'm getting an ActiveRecord::EagerLoadPolymorphicError with > > > > > paginating_find when I include an :include => :commentable > parameter > > > > > in the call. This doesn't happen when I use will_paginate instead. > > > > > > > After testing and confirming this outside of CE, I am wondering if > > > > > it's possible and of interest to the community to replace > > > > > paginating_find with will_paginate within CE. What would be the > > > > > pitfalls? Any feedback is very welcome. > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "CommunityEngine" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/communityengine?hl=en -~----------~----~----~----~------~----~------~--~---
