DBA_HIST_LIBRARYCACHE displays historical statistics about library cache performance and activity. This view contains snapshots of V$LIBRARYCACHE.

Column Datatype NULL Description
DBID NUMBER NOT NULL Database ID for the snapshot
INSTANCE_NUMBER NUMBER NOT NULL Instance number for the snapshot
NAMESPACE VARCHAR2(15) NOT NULL Library cache namespace
GETS NUMBER   Number of times a lock was requested for objects of the namespace
GETHITS NUMBER   Number of times an object's handle was found in memory
PINS NUMBER   Number of times a PIN was requested for objects of the namespace
PINHITS NUMBER   Number of times all of the metadata pieces of the library object were found in memory
RELOADS NUMBER   Any PIN of an object that is not the first PIN performed since the object handle was created, and which requires loading the object from disk
INVALIDATIONS NUMBER   Total number of times objects in the namespace were marked invalid because a dependent object was modified
DLM_LOCK_REQUESTS NUMBER   Number of GET requests lock instance locks
DLM_PIN_REQUESTS NUMBER   Number of PIN requests lock instance locks
DLM_PIN_RELEASES NUMBER   Number of release requests PIN instance locks
DLM_INVALIDATION_REQUESTS NUMBER   Number of GET requests for invalidation instance locks
DLM_INVALIDATIONS NUMBER   Number of invalidation pings received from other instances