Sequel::Batches

This dataset extension provides the method #in_batches. The method splits dataset in parts and yields it.

Note: currently only PostgreSQL database is supported.

You can set the following options:

pk

Overrides primary key of your dataset. This option is required in case your table doesn't have a real PK, otherwise you will get Sequel::Extensions::Batches::MissingPKError.

Note that you have to provide columns that don't contain NULL values, otherwise this may not work as intended. You will receive Sequel::Extensions::Batches::NullPKError in case batch processing detects a NULL value on it's way, but it's not guaranteed since it doesn't check all the rows for performance reasons.

of

Sets chunk size (1000 by default).

start

A hash { [column]: <start_value> } that represents frame start for batch processing. Note that you will get Sequel::Extensions::Batches::InvalidPKError in case you provide a hash with wrong keys (ordering matters as well).

finish

Same as start but represents the frame end.

Installation

Add this line to your application's Gemfile:

gem 'sequel-batches'

And then execute:

$ bundle

Or install it yourself as:

$ gem install sequel-batches

Usage

In order to use the feature you should enable the extension

Sequel::DATABASES.first.extension :batches

And then the method becomes available on dataset

User.where(role: "admin").in_batches(of: 4) do |ds|
  ds.delete
end

Finally, here's an example including all the available options

Event.where(type: "login").in_batches(of: 4, pk: [:project_id, :external_user_id], start: { project_id: 2, external_user_id: 3 }, finish: { project_id: 5, external_user_id: 70 }) do |ds|
  ds.delete
end

Development

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 version.rb, 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.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/sequel-batches. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

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

Code of Conduct

Everyone interacting in the Sequel::Batches project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.