Using Thread to help ruby garbage collection

thread_gc.rb

# GC.start does not help here, the heap keeps growing
class Foo < ActiveRecord::Base
  def self.process_all!
    all.each { |record|
      puts "Processing #{ record.id }"

      record.high_mem_process
      record.save!

      GC.start
    }
  end
end

# GC.start cleans the heap after the thread exits
class Foo < ActiveRecord::Base
  def self.process_one!( id )
    puts "Processing #{ id }"

    record = find id
    record.high_mem_process
    record.save!
  end

  def self.process_all!
    ids = select :id

    ids.each { |r|
      t = Thread.new { process_one! r.id }
      t.join

      GC.start
    }
  end
end