begin_isolated_db_transaction

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 227
      def begin_isolated_db_transaction(isolation) # :nodoc:
        # From MySQL manual: The [SET TRANSACTION] statement applies only to the next single transaction performed within the session.
        # So we don't need to implement #reset_isolation_level
        execute_batch(
          ["SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}", "BEGIN"],
          "TRANSACTION",
          allow_retry: true,
          materialize_transactions: false,
        )
      end