Finding mongoDB records in batches (using mongoid ruby adapter)

Question

Using rails 3 and mongoDB with the mongoid adapter, how can I batch finds to the mongo DB? I need to grab all the records in a particular mongo DB collection and index them

Answer 1

With Mongoid, you don't need to manually batch the query.

In Mongoid, Model.all returns a Mongoid::Criteria instance. Upon calling #each on this Criteria, a Mongo driver cursor is instantiated and used to iterate over the records. This underlying Mongo driver cursor already batches all records. By default the batch_size is 100.

For more information on this topic, read this comment from the Mongoid author and maintainer.

In summary, you can just do this:

Model.all.each do |r|
  Sunspot.index(r)
end