On Oct 28, 10:02 am, AWD Switzerland <[email protected]> wrote: > Hi There > > Is active record 3.1.1 supposed to be threadsafe? > In other words, should the following (concurrent access to a model) > work? > > Thread.new do MyModel.where(some_condition).first end > Thread.new do MyModel.where(some_condition).first end > > I ask because upon the answer, it depends which component should handle > synchronization, and in consequence, which component to patch/fix. > Rails added thread safety back in 2.1 or 2.2 so current versions should be threadsafe.
> A bit of background: We stumbled over a concurrency issue when using > capybara-webkit with rails3.1. We traced the issue down to one thread > querying and trying to accessing the cache while another thread cleared > the same cache. > Assuming active record 3.1.1 is supposed to be threadsafe, then the > culprit for the issue would be > ActiveRecord::ConnectionAdapters::QueryCache, which doesn't synchronize > access to its @query_cache. > Seehttps://github.com/awd-switzerland/rails/commit/22aeda0f0553fdcabca15... > for a possible way to resolve that. However, I'm not sure in which layer > the rails team wants to handle synchronisation. In theory I don't think this is needed because different threads should be using different connection objects (there's supposed to be a pool of connection objections, and any member of the pool is only ever used by one thread at a time. You might also want to ask on the rails- core list Fred > Also notice that the patch is naive in that it simply assumes thread > support in ruby to be enabled. > > Best regards > Stefan Rusterholz > > -- > Posted viahttp://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.
