select
  inst_id,                                 -- INST_ID NUMBER
  decode(                                  -- POLICY_EVENT VARCHAR2(20)
    policy_event, 0,'none',1,'glru_on',2,'glru_off', 3,'policy_on',4,'policy_off',5,'initiate_affinity',6,'grab_affinity', 7,'push_affinity',8,'initiate_read_mostly',9,'grab_read_mostly', 10,'dissolve_affinity',11,'dissolve_read_mostly',12,'drop_dissolve', 14,'collision_dissolve',15,'table_dissolve',16,'anti_dissolve'),
  data_object_id,                          -- DATA_OBJECT_ID NUMBER
  target_instance_number,                  -- TARGET_INSTANCE_NUMBER NUMBER
  event_date                               -- EVENT_DATE VARCHAR2(20)
from
  x$policy_history