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Oracle® Database Reference
10g Release 1 (10.1)

Part Number B10755-01
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V$BH

This is a Real Application Clusters view. This view gives the status and number of pings for every buffer in the SGA.

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 buffer:
  • 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 This column is obsolete and maintained for backward compatibility.
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 The 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_CLASS NUMBER The 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.
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
DIRTY VARCHAR2(1) Y - block modified
TEMP VARCHAR2(1) Y - temporary block
PING VARCHAR2(1) Y - block pinged
STALE VARCHAR2(1) Y - block is stale
DIRECT VARCHAR2(1) Y - direct block
NEW VARCHAR2(1) Always set to N. This column is obsolete and maintained for backward compatibility.
OBJD NUMBER Database object number of the block that the buffer represents
TS# NUMBER Tablespace number of block