Merge pull request rails#49089 from emilyqiu1005/emilyqiu/add-kill-to-mysql-read-queries

Allow KILL queries on read-only connections for mysql

Author: rafaelfranca

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

@@ -5,7 +5,7 @@ module ConnectionAdapters
     module MySQL
       module DatabaseStatements
         READ_QUERY = AbstractAdapter.build_read_query_regexp(
-          :desc, :describe, :set, :show, :use
+          :desc, :describe, :set, :show, :use, :kill
         ) # :nodoc:
         private_constant :READ_QUERY
 

activerecord/test/cases/adapters/abstract_mysql_adapter/adapter_prevent_writes_test.rb

@@ -95,6 +95,15 @@ def test_doesnt_error_when_a_use_query_is_called_while_preventing_writes
     end
   end
 
+  def test_doesnt_error_when_a_kill_query_is_called_while_preventing_writes
+    ActiveRecord::Base.while_preventing_writes do
+      conn_id = @conn.execute("SELECT CONNECTION_ID() as connection_id").to_a[0][0]
+      assert_raises(ActiveRecord::QueryCanceled) do
+        @conn.execute("KILL QUERY #{conn_id}")
+      end
+    end
+  end
+
   private
     def with_example_table(definition = "id int auto_increment primary key, number int, data varchar(255)", &block)
       super(@conn, "ex", definition, &block)