The SET JOINOP NOTIMEOUT option can be used in tracing query performance. This statement turns the optimizer timeout feature off. With timeout on, the optimizer stops checking for further query execution plans when it believes that the best plan it has found takes less time to execute than the amount of time already spent searching for a plan. If you issue a SET JOINOP NOTIMEOUT statement, the optimizer continues searching query plans. This option is often used with the SET QEP option to ensure that the optimizer is picking the best possible query plan.