1 files changed, 32 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/runtime_registry.rb b/activerecord/lib/active_record/runtime_registry.rb
new file mode 100644
index 0000000000..3f0ac68143
--- /dev/null
+++ b/activerecord/lib/active_record/runtime_registry.rb
@@ -0,0 +1,32 @@
+require 'active_support/per_thread_registry'
+
+module ActiveRecord
+  # This is a registry class for storing local variables in active record. The
+  # class allows you to access variables that are local to the current thread.
+  # These thread local variables are stored as attributes in the
+  # +RuntimeRegistry+ class.
+  #
+  # You can access the thread local variables by calling a variable's name on
+  # the +RuntimeRegistry+ class. For example, if you wanted to obtain the
+  # connection handler for the current thread, you would invoke:
+  #
+  #   ActiveRecord::RuntimeRegistry.instance.connection_handler
+  #
+  # The +PerThreadRegistry+ module will make a new +RuntimeRegistry+ instance
+  # and store it in +Thread.current+. Whenever you make a call for an attribute
+  # on the +RuntimeRegistry+ class, the call will be sent to the instance that
+  # is stored in +Thread.current+.
+  #
+  # Note that you can also make the following call which would provide an
+  # equivalent result as the previous code:
+  #
+  #   ActiveRecord::RuntimeRegistry.connection_handler
+  #
+  # However, this is less performant because it makes a call to +method_missing+
+  # before it sends the method call to the +instance+.
+  class RuntimeRegistry
+    extend ActiveSupport::PerThreadRegistry
+
+    attr_accessor :connection_handler, :sql_runtime, :connection_id
+  end
+end