You can use Oracle Database Resource Manager to set the maximum queue timeout limit so that parallel statements do not stay in the queue for long periods of time. Using Oracle Database Resource Manager you can map parallel statement sessions to different consumer groups that each have specific maximum timeout limits in a resource plan.
To manage the queue timeout, the parallel_queue_timeout
parameter is used with the CREATE_PLAN_DIRECTIVE
procedure or the new_parallel_queue_timeout
parameter is used with the UPDATE_PLAN_DIRECTIVE
procedure in the DBMS_RESOURCE_MANAGER
package. The parallel_queue_timeout
and new_parallel_queue_timeout
parameters specify the time in seconds that a statement can remain in a consumer group parallel statement queue. After the timeout period has expired, the statement is terminated with error ORA-7454
and removed from the parallel statement queue.