Ruby 2.7 - Setting $ special variables to non-nil value is now warned
In Ruby 2.7, setting special variable $, $; $/ $\ to non-nil values will now show a deprecated warning
Eager loading Active Storage models to avoid N+1 issues
Removing N+1 queries when we access the Active Storage attachments associated with an ActiveRecord model.Rails adds jitter to ActiveJob::Exceptions.retry_on
Rails adds jitter to ActiveJob::Exceptions.retry_on to cater to thundering herd effectRuby Hash#transform_keys now accepts a hash that maps existing keys to new keys
Ruby Hash#transform_keys now also accepts a hash that maps the existing hash keys to new keys
Rails has added strict loading mode to prevent lazy loading
Rails has added strict loading mode to prevent lazy loading of associations and help avoid N + 1 queriesRails adds config rake_eager_load
Rails has added the option to eager load all the registered name spaces in rake tasks.Rails has added support for automatic database connection switching from primary to the replica
Rails has added support for automatic database connection switching from primary to the replicaRuby 2.7 removes taint checking mechanism
Ruby 2.7 access and setting of $SAFE is now always warned. $SAFE will become a normal global variable in Ruby 3.0Rails 6.1 adds at option to perform_enqueued_jobs test helper
Rails 6.1 has added at option to perform_enqueued_jobs test helper to run only jobs which are scheduled at or before the passed in time
Rails adds ActiveRecord API for switching multiple database connections
Rails adds ActiveRecord API connects_to and connected_to for switching connections to support multiple databases.