DBA_HIST_LIBRARYCACHE displays historical statistics about library cache performance and activity. This view contains snapshots of V$LIBRARYCACHE.
| Column | Datatype | NULL | Description |
|---|---|---|---|
SNAP_ID |
NUMBER |
NOT NULL |
Unique snapshot ID |
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 |