Merge pull request #33985 from eugeneius/attribute_methods_schema_cache

Only define attribute methods from schema cache

5 files changed, 30 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/schema_cache.rb b/activerecord/lib/active_record/connection_adapters/schema_cache.rb
index c29cf1f9a1..c10765f42d 100644
--- a/activerecord/lib/active_record/connection_adapters/schema_cache.rb
+++ b/activerecord/lib/active_record/connection_adapters/schema_cache.rb
@@ -77,6 +77,11 @@ module ActiveRecord
         }]
       end
 
+      # Checks whether the columns hash is already cached for a table.
+      def columns_hash?(table_name)
+        @columns_hash.key?(table_name)
+      end
+
       # Clears out internal caches
       def clear!
         @columns.clear
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index fc564d59e2..600825659b 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -282,6 +282,10 @@ module ActiveRecord
         TypeCaster::Map.new(self)
       end
 
+      def _internal? # :nodoc:
+        false
+      end
+
       private
 
         def cached_find_by_statement(key, &block)
diff --git a/activerecord/lib/active_record/internal_metadata.rb b/activerecord/lib/active_record/internal_metadata.rb
index 3626a13d7c..88b0c828ae 100644
--- a/activerecord/lib/active_record/internal_metadata.rb
+++ b/activerecord/lib/active_record/internal_metadata.rb
@@ -8,6 +8,10 @@ module ActiveRecord
   # as which environment migrations were run in.
   class InternalMetadata < ActiveRecord::Base # :nodoc:
     class << self
+      def _internal?
+        true
+      end
+
       def primary_key
         "key"
       end
diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb
index 538659d6bd..2ee6119158 100644
--- a/activerecord/lib/active_record/railtie.rb
+++ b/activerecord/lib/active_record/railtie.rb
@@ -140,7 +140,19 @@ end_error
     initializer "active_record.define_attribute_methods" do |app|
       config.after_initialize do
         ActiveSupport.on_load(:active_record) do
-          descendants.each(&:define_attribute_methods) if app.config.eager_load
+          if app.config.eager_load
+            descendants.each do |model|
+              # SchemaMigration and InternalMetadata both override `table_exists?`
+              # to bypass the schema cache, so skip them to avoid the extra queries.
+              next if model._internal?
+
+              # If there's no connection yet, or the schema cache doesn't have the columns
+              # hash for the model cached, `define_attribute_methods` would trigger a query.
+              next unless model.connected? && model.connection.schema_cache.columns_hash?(model.table_name)
+
+              model.define_attribute_methods
+            end
+          end
         end
       end
     end
diff --git a/activerecord/lib/active_record/schema_migration.rb b/activerecord/lib/active_record/schema_migration.rb
index f2d8b038fa..1fca1a18f6 100644
--- a/activerecord/lib/active_record/schema_migration.rb
+++ b/activerecord/lib/active_record/schema_migration.rb
@@ -10,6 +10,10 @@ module ActiveRecord
   # to be executed the next time.
   class SchemaMigration < ActiveRecord::Base # :nodoc:
     class << self
+      def _internal?
+        true
+      end
+
       def primary_key
         "version"
       end