On Thu, Dec 22, 2011 at 11:58 AM, Alexey Petrushin <[email protected]>wrote:
> Hello, can You please explain to me why we can't use Thread.new in > :after_save? > > Let's suppose the following situation: we have a blog and using remote > search engine (in form of http service) to index it. So, after any > change to the blog post we should also make an http call to notify > search service about changes. In the code it will look something like > this: > > class Post < ActiveRecord::Base > after_save do |model| > Thread.new do > # making remote HTTP call. > remote_search_engine.update model > end > end > end > > class PostController < ActiveController::Base > def upate > post = Post.by_id(params[:id]) > post.update_attributes params[:post] > render json: post > end > end > > Theoretically it should work. It should update post, immediately return > JSON response, > and finish call to the search engine sometime later > But nobody does this, why? > > For a very long time, I thought that nobody using this technique because > this external http call will blocks the whole VM, so it make no sense to > use it. > But a couple days ago I found that this is actually wrong, this http > call will not block the VM (Fibur as a prove > https://gist.github.com/1498215 ). > > So, now I wondering - what other problems are out there? Why nobody uses > this and use instead tools like delayed_job and resque? > > My guess would be because of the overhead in managing threads. If your rails code is spawning a new thread after every save, that could get dangerous really quickly. So then you would need some kind of thread manager to make sure that threads are properly closing, that threads aren't interfering with each other (what if you save a model twice in quick succession and, for one reason or another, the first thread takes longer to complete so effectively the results of this thread win out in the end), etc? > Thanks! > > -- > Posted via http://www.ruby-forum.com/. > > -- > You received this message because you are subscribed to the Google Groups > "Ruby on Rails: Talk" 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/rubyonrails-talk?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" 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/rubyonrails-talk?hl=en.
