Patch for load times with pg_type loading in AR

- See #14615
- See rails/rails#19578

config/initializers/zz_patch_activerecord_type_loading.rb

@@ -0,0 +1,38 @@
+# Activerecord every time it mades a connection brings all the `pg_type`
+# data into a cache in order to do the relation between pg types and rails
+# types
+#
+# What is the problem?
+#
+# Well in our users database we have 300K type. AR picks ~142K which leads to
+# spent ~1.3s picking the data and ~0.5s in processing those records so we end
+# spending about ~2s or more without needed in all our in_database operations
+#
+# How this fix works?
+#
+# Well, we filter all the table types (table, analysis tables, overviews) because
+# in our app they aren't going to be used and in case they're need, Rails is going
+# to query the database for it, so no problem.
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module OID # :nodoc:
+        class TypeMapInitializer # :nodoc:
+          def query_conditions_for_initial_load(type_map)
+            known_type_names = type_map.keys.map { |n| "'#{n}'" }
+            known_type_types = %w('r' 'e' 'd')
+            <<-SQL % [known_type_names.join(", "), known_type_types.join(", ")]
+              LEFT JOIN pg_type as tt ON (tt.typtype = 'c' AND tt.typarray = t.oid AND tt.typinput = 'record_in(cstring,oid,integer)'::regprocedure)
+              WHERE
+                tt.oid is null
+                AND (t.typname IN (%s)
+                OR t.typtype IN (%s)
+                OR t.typinput = 'array_in(cstring,oid,integer)'::regprocedure
+                OR t.typelem != 0)
+            SQL
+          end
+        end
+      end
+    end
+  end
+end