7.233 V$GC_ELEMENT

V$GC_ELEMENT displays one entry for each global cache resource that is used by the buffer cache. The name of the global cache resource that corresponds to a lock element is {'BL', indx, class}. This is an Oracle Real Application Clusters view.

Column Datatype Description

GC_ELEMENT_ADDR

RAW(4 | 8)

Address of the lock element that contains the PCM lock that is covering the buffer. If more than one buffer has the same address, then these buffers are covered by the same PCM lock.

INDX

NUMBER

Platform specific lock manager identifier

CLASS

NUMBER

Platform specific lock manager identifier

GC_ELEMENT_NAME

NUMBER

Name of the lock that contains the PCM lock that is covering the buffer

MODE_HELD

NUMBER

Platform dependent value for lock mode held; often: 3 = share; 5 = exclusive

BLOCK_COUNT

NUMBER

Number of blocks covered by PCM lock

RELEASING

NUMBER

Nonzero if PCM lock is being downgraded

ACQUIRING

NUMBER

Nonzero if PCM lock is being upgraded

WRITING

NUMBER

If the GC_ELEMENT is being written, the write status

RECOVERING

NUMBER

If the GC_ELEMENT is being recovered, the recovery status

LOCAL

NUMBER

Zero if the GC_ELEMENT is local, one if it is global

FLAGS

NUMBER

Process level flags for the lock element

CON_ID

NUMBER

The ID of the container to which the data pertains. 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