ActiveRecord::FindEachOrdered

Behave's like ActiveRecord's #find_each method, but allows sorting by a column other than the primary key.

There are times when you need to load a large number of records, but sorting by the primary key is undesired, or prohibitely expensive. Sorting by the primary key may cause the database planner to avoid an index that would otherwise be more helpful.

Add this line to your application's Gemfile:

gem 'activerecord-find_each_ordered'

And then execute:

$ bundle

Or install it yourself as:

$ gem install activerecord-find_each_ordered

yesterday = 1.day.ago
Item.
  where(purchased_at: (yesterday.beginning_of_day..yesterday.end_of_day)).
  find_each_ordered(:purchased_at, batch_size: 500) do |item|

  # work with each item instance
end

There are other gems that try to solve this same problem. They all end up with very similar implementations (mostly because we all start from the source for #find_each). After I started my implementation, but before publishing it, I discovered https://github.com/nambrot/ar-find-in-batches-with-order. If has a little bit more flexibility - the ability to infer the desired sort order based on order declarations on the Relation, support for descending sorts, support for yielding the entire batch or just a record at a time. If those features are interesting to you, you are probably better off using that gem. I stuck with my implementation because I didn't need the complexity of those other features, and I built tests to prove the features I did need.

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in the gemspec, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/joshuaflanagan/activerecord-find_each_ordered.

The gem is available as open source under the terms of the MIT License.