V$CACHE

V$CACHE displays information from the block header of each block in the SGA of the current instance as related to particular database objects. This is an Oracle Real Application Clusters view.

Column Datatype Description

FILE#

NUMBER

Data file identifier number (to find the file name, query DBA_DATA_FILES or V$DBFILE)

BLOCK#

NUMBER

Block number

CLASS#

NUMBER

Class number

STATUS

VARCHAR2(10)

Status of the block:

  • free - Not currently in use

  • xcur - Exclusive

  • scur - Shared current

  • cr - Consistent read

  • read - Being read from disk

  • mrec - In media recovery mode

  • irec - In instance recovery mode

XNC

NUMBER

Number of PCM x to null lock conversions due to contention with another instance. This column is obsolete and maintained for backward compatibility.

FORCED_READS

NUMBER

Number of times the block had to be reread from the cache because another instance has forced it out of this instance's cache by requesting the lock on the block in exclusive mode

FORCED_WRITES

NUMBER

Number of times GCS had to write this block to cache because this instance had used the block and another instance had requested the lock on the block in a conflicting mode

NAME

VARCHAR2(128)

Name of the database object containing the block

PARTITION_NAME

VARCHAR2(128)

Name of the partition (null for nonpartitioned objects)

KIND

VARCHAR2(15)

Type of the database object:

  • INDEX

  • TABLE

  • CLUSTER

  • VIEW

  • SYNONYM

  • SEQUENCE

  • PROCEDURE

  • FUNCTION

  • PACKAGE

  • NON-EXISTENT

  • PACKAGE BODY

  • TRIGGER

  • TYPE

  • TYPE BODY

  • TABLE PARTITION

  • INDEX PARTITION

  • LOB

  • LIBRARY

  • JAVA SOURCE

  • JAVA CLASS

  • JAVA RESOURCE

  • JAVA DATA

  • UNDO

OWNER#

NUMBER

Owner number

LOCK_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.

LOCK_ELEMENT_NAME

NUMBER

Name 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.

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