RetryOnDeadlock

RetryOnDeadlock is a Ruby gem designed to handle deadlocks in ActiveRecord transactions by automatically retrying them with exponential backoff. This gem is particularly useful in high-concurrency environments where deadlocks are common.

Add this line to your application's Gemfile:

gem 'retry_on_deadlock'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install retry_on_deadlock

To use RetryOnDeadlock, simply include it in your ActiveRecord transactions. By default, the gem retries transactions up to 3 times when a deadlock occurs.

Here is an example:

Car.transaction(retry_on_deadlock: true) do
  car = Car.find(1)
  car.update!(name: "Updated Name")
end

You can configure the gem to suit your needs. For example:

RetryOnDeadlock.configure do |config|
  config.max_retries = 5 # Number of retries before giving up
  config.enable_logging = true # Enable logging of retry attempts
  config.log_level = :info # Log level for retry logs
  config.logger = Logger.new(STDOUT) # Custom logger
  config.always_retry = false # Always retry transactions unless explicitly disabled
end

RetryOnDeadlock does not retry nested transactions. If a deadlock occurs within a nested transaction, the error will be raised immediately.

1. Increased Database Load:

   • Retrying transactions can increase the load on your database, especially if retries are frequent. Use with caution in high-traffic applications.

2. Nested Transactions:

   • The gem does not retry nested transactions. Ensure your application can handle errors in such cases.

3. Exceeding Max Retries:

   • If the maximum number of retries is exceeded, the original ActiveRecord::Deadlocked error will be raised. Make sure your application handles this scenario gracefully.

4. Compatibility:

   • The gem is designed for ActiveRecord and assumes a PostgreSQL database. It may not work as expected with other databases or ORMs.

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

This will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

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