Fixed issue #12327

activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb

@@ -157,8 +157,8 @@ def exec_query(sql, name = 'SQL', binds = [])
 
         def exec_delete(sql, name = 'SQL', binds = [])
           log(sql, name, binds) do
-            result = binds.empty? ? exec_no_cache(sql, binds) :
-                                    exec_cache(sql, binds)
+            result = without_prepared_statement?(binds) ? exec_no_cache(sql, binds) :
+                                                          exec_cache(sql, binds)
             affected = result.cmd_tuples
             result.clear
             affected

activerecord/test/cases/base_test.rb

@@ -566,6 +566,15 @@ def test_create_without_prepared_statement
     assert_equal topic, Topic.find(topic.id)
   end
 
+  def test_destroy_without_prepared_statement
+    topic = Topic.create(title: 'foo')
+    Topic.connection.unprepared_statement do
+      Topic.find(topic.id).destroy
+    end
+
+    assert_equal nil, Topic.find_by_id(topic.id)
+  end
+
   def test_blank_ids
     one = Subscriber.new(:id => '')
     two = Subscriber.new(:id => '')