I remember i was working on a project where there was a large set of data in the resultset and on the basis of that data i have to update some other model but i was unable to do it in batches due to some reason. So i was searching for a method in ruby which can do this thing for me. so i found a method as below:

in_groups_of(number, fill_with = nil)

what it use to do is it Splits or iterates over the array in groups of size number. for ex:

results.in_groups_of(100, false) {|res| 
      res_hash = {}
        res.each do |ar|
          res_hash[ar['cr_id']] = {'profile_id'=>ar['id']}
        end        
        if res_hash.count > 0          
           User.update(res_hash.keys, res_hash.values)
        end
      }

so it was taking the 100 records in res object and than i was iterating it and creating a array and than i was updating the user record at one go. So it was very helpful for me that time.

Note: if there are less than the no_of_records(100 in case) we specify it will create a single group. and the remaining ones in the second group or so.

where results = User.find(:all)