7 Replies Latest reply on Aug 18, 2014 4:04 PM by BPeaslandDBA

    limit parralel in rac



        we have an RAC with 4 nodes,  Some queries  overload database with a hight degree of parallel :  192 degree of parallel, paralle on 4 instances and i found 384 actives sessions for 1 query!!


      I need your help to limit parallel  and avoid to overload database.


      I configure the degree of every (used) table to  parallel 8 (Alter table XXX parallel 8) but it's notre used.

      Some parameters of instance :


      cpu_count      24


      show parameter parallel
      fast_start_parallel_rollback         string     LOW
      parallel_adaptive_multi_user         boolean     TRUE
      parallel_automatic_tuning         boolean     FALSE
      parallel_degree_limit             string     32
      parallel_degree_policy             string     LIMITED
      parallel_execution_message_size      integer     16384
      parallel_force_local             boolean     FALSE
      parallel_instance_group          string
      parallel_io_cap_enabled          boolean     FALSE
      parallel_max_servers             integer     960
      parallel_min_percent             integer     0
      parallel_min_servers             integer     0
      parallel_min_time_threshold         string     AUTO
      parallel_server              boolean     TRUE
      parallel_server_instances         integer     4
      parallel_servers_target          integer     64
      parallel_threads_per_cpu         integer     2
      recovery_parallelism             integer     0


      Any help will be appreciated :-)