DBA_HIST_LIBRARYCACHE

5.6 DBA_HIST_LIBRARYCACHE

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
`CON_DBID`	`NUMBER`		The database ID of the PDB for the sampled session
`CON_ID`	`NUMBER`		The ID of the container that `CON_DBID` identifies. Possible values include: `0`: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs. `1`: This value is used for rows containing data that pertain to only the root n: Where n is the applicable container ID for the rows containing data