find_in_batches(options = {}) — ActiveRecord::Batches::ClassMethods

find_in_batches(options = {})

Yields each batch of records that was found by the find options as an array. The size of each batch is set by the :batch_size option; the default is 1000.

You can control the starting point for the batch processing by supplying the :start option. This is especially useful if you want multiple workers dealing with the same processing queue. You can make worker 1 handle all the records between id 0 and 10,000 and worker 2 handle from 10,000 and beyond (by setting the :start option on that worker).

It’s not possible to set the order. That is automatically set to ascending on the primary key (“id ASC”) to make the batch ordering work. This also mean that this method only works with integer-based primary keys. You can’t set the limit either, that’s used to control the the batch sizes.

Example:

Person.find_in_batches(:conditions => "age > 21") do |group|
  sleep(50) # Make sure it doesn't get too crowded in there!
  group.each { |person| person.party_all_night! }
end

Parameters

options opt = {}

Source

# File activerecord/lib/active_record/batches.rb, line 55
      def find_in_batches(options = {})
        raise "You can't specify an order, it's forced to be #{batch_order}" if options[:order]
        raise "You can't specify a limit, it's forced to be the batch_size"  if options[:limit]

        start = options.delete(:start).to_i
        batch_size = options.delete(:batch_size) || 1000

        proxy = scoped(options.merge(:order => batch_order, :limit => batch_size))
        records = proxy.find(:all, :conditions => [ "#{table_name}.#{primary_key} >= ?", start ])

        while records.any?
          yield records

          break if records.size < batch_size
          
          last_value = records.last.id
          
          raise "You must include the primary key if you define a select" unless last_value.present?
          
          records = proxy.find(:all, :conditions => [ "#{table_name}.#{primary_key} > ?", last_value ])
        end
      end

Defined in activerecord/lib/active_record/batches.rb line 55 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveRecord::Batches::ClassMethods

Signature

Parameters