Issue: Configuring Active Record to Use Different Base Classes for Sharded and Non-Sharded Models

[rishav-enigma]

Background
In our legacy Rails application, we have been using the active_record_shards gem to handle database sharding. Prior to upgrading to Rails 7.2, we patched certain models (e.g., Doorkeeper models) using not_sharded, ensuring they always connected to the primary database:

Doorkeeper::Application.class_eval do
  not_sharded
  ...
end

With the upgrade, we introduced two base classes to handle this explicitly:

class GlobalRecord < ActiveRecord::Base
  self.abstract_class = true
  connects_to database: { writing: :primary }
end

class ApplicationRecord < ActiveRecord::Base
  self.abstract_class = true
  ...
  # Defaults to shards
end

Problem
Instead of manually replacing every model’s superclass (e.g., Doorkeeper::Application < GlobalRecord), we are looking for a configuration-based solution that allows certain models to automatically connect to the primary database while keeping the rest on sharded connections.

Is there a recommended approach in Rails 7.2 to handle this use case without modifying every model explicitly?

Expected Behavior
A way to configure specific models (e.g., Doorkeeper::Application) to always use GlobalRecord or connect to :primary without manually changing every occurrence.
Ideally, this would be a simple Active Record configuration instead of modifying all model definitions.
Any guidance or best practices for handling this in Rails 7.2 would be greatly appreciated.