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 a Real Application Clusters view.

Column Datatype Description
FILE# NUMBER Datafile identifier number (to find the filename, query DBA_DATA_FILES or V$DBFILE)
BLOCK# NUMBER Block number
CLASS# NUMBER Class number
STATUS VARCHAR2(6) 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 This column is obsolete and maintained for backward compatibility.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(30) Name of the database object containing the block
PARTITION_NAME VARCHAR2(30) Name of the partition (null for non-partitioned 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.