New Features

• A Sequel::Model.shape_friendly accessor has been added. If it is set to true, then Sequel::Model instances use shape-friendly initialization, setting all possible instance variables used by all plugins to nil.

  This can significantly improve performance in many cases. However, there are other cases where it can decrease performance. Currently, shape-friendly behavior is opt-in, and users are encouraged to test it and see what performance effect is has in their application. Depending on feedback, shape friendliness may be made the default in a future Sequel version. If you would like to test out shape friendliness, set the following before creating model classes:

  Sequel::Model.shape_friendly = true
  

  If your Sequel model uses custom instance variables, you should register them inside the model:

  set_model_instance_variables(:@iv1, :@iv2)
  

  If you develop a Sequel plugin, and that plugin sets instance variables for model instances, you should register those instance variables inside the plugin’s ClassMethods module (you may have to add a ClassMethods module if the plugin currently has InstanceMethods but not ClassMethods):

  module ClassMethods
    Plugins.model_instance_variable(self, :@iv1, :@iv2)
  end
  

  Shape friendliness can increase the size of marshallabled objects, which has the potential to break things if you are storing the marshalled object in location with a fixed maximum size.

Other Improvements

• The connection_expiration extension now sets up expiration for connections already in the pool. Previously, it only setup expiration for new connections.

Backwards Compatibility

• If you are currently expecting that Sequel::Model internal instance variables may not be defined, you should update your code to work with shape-friendly models, which will set the instance variables to nil during initialization.