gistfile1

Aggregate.transaction do
  write_count = 0
  HourlyAggregate.connection.create_savepoint
  Aggregate.find(...).each do |aggregate|
    ...
    write_count += 1 # Only if you actually write
    if write_count % 1000 == 0
      HourlyAggregate.connection.release_savepoint
      HourlyAggregate.connection.create_savepoint
    end
  end
end