Merge pull request rails#52272 from fatkodima/skip-triggering-instantiation-notification

Skip triggering "instantiation.active_record" notification when there are no records

Author: byroot

activerecord/lib/active_record/querying.rb

@@ -71,6 +71,8 @@ def _query_by_sql(connection, sql, binds = [], preparable: nil, async: false, al
     end
 
     def _load_from_sql(result_set, &block) # :nodoc:
+      return [] if result_set.empty?
+
       column_types = result_set.column_types
 
       unless column_types.empty?

activerecord/test/cases/instrumentation_test.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "cases/helper"
+require "models/author"
 require "models/book"
 require "models/clothing_item"
 
@@ -170,6 +171,22 @@ def test_payload_connection_with_query_cache_enabled
     ensure
       ActiveSupport::Notifications.unsubscribe(subscriber) if subscriber
     end
+
+    def test_no_instantiation_notification_when_no_records
+      author = Author.create!(name: "David")
+
+      called = false
+      subscriber = ActiveSupport::Notifications.subscribe("instantiation.active_record") do
+        called = true
+      end
+
+      Author.where(id: 0).to_a
+      author.books.to_a
+
+      assert_equal false, called
+    ensure
+      ActiveSupport::Notifications.unsubscribe(subscriber) if subscriber
+    end
   end
 
   module TransactionInSqlActiveRecordPayloadTests