SHARED POOL V$LIBRARYCACHE STATISTIC NOTES:
  • Namespace - Library cache namespace (SQL AREA, TABLE/PROCEDURE, BODY, TRIGGER, INDEX, CLUSTER, OBJECT, PIPE)
  • Gets - Number of times the system requests handles to library objects belonging to this namespace
  • GetHits - Number of times the handles are already allocated in the cache. If the handle is not already allocated, it is a miss. The handle is then allocated and inserted into the cache.
  • GetHit Ratio - Number of GETHITS divided by GETS. Values close to 1 indicate that most of the handles the system has tried to get are cached.
  • Pins - Number of times the system issues pin requests for objects in the cache in order to access them.
  • PinHits - Number of times that objects the system is pinning and accessing are already allocated and initialized in the cache. Otherwise, it is a miss, and the system has to allocate it in the cache and initialize it with data queried from the database or generate the data.
  • PinHit Ratio - Number of PINHITS divided by number of PINS. Values close to 1 indicate that most of the objects the system has tried to pin and access have been cached.
  • Reloads - Number of times that library objects have to be reinitialized and reloaded with data because they have been aged out or invalidated.
  • Invalidations - Number of times that non-persistent library objects (like shared SQL areas) have been invalidated.

  • GetHit Ratio and PinHit Ratio should be > 70