Dynamic Performance (V$) Views, 19 of 179

V$BH

This is an Oracle Parallel Server 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 filename, query DBA_DATA_FILES or V$DBFILES)

BLOCK#

NUMBER

Block number

CLASS#

NUMBER

The class number

STATUS

VARCHAR2(1)

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 This column is obsolete but is retained for historical compatibility.

LOCK_ELEMENT_ADDR

RAW(4)

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_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 made re-read from disk because another instance had forced it out of this instance's cache by requesting the PCM lock on this block in lock mode.

FORCED_WRITES

NUMBER

Number of times DBWR had to write this block to disk because this instance had dirtied the block and another instance had requested the PCM lock on the block in 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Always set to N. This column is obsolete but is retained for historical compatibility

OBJD

NUMBER

Database object number of the block that the buffer represents

TS#

NUMBER

Tablespace number of block

Column	Datatype	Description
`FILE#`	`NUMBER`	Datafile identifier number (to find filename, query `DBA_DATA_FILES` or `V$DBFILES`)
`BLOCK#`	`NUMBER`	Block number
`CLASS#`	`NUMBER`	The class number
`STATUS`	`VARCHAR2(1)`	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 but is retained for historical compatibility.
`LOCK_ELEMENT_ADDR`	`RAW(4)`	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_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 made re-read from disk because another instance had forced it out of this instance's cache by requesting the PCM lock on this block in lock mode.
`FORCED_WRITES`	`NUMBER`	Number of times DBWR had to write this block to disk because this instance had dirtied the block and another instance had requested the PCM lock on the block in 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 but is retained for historical compatibility
`OBJD`	`NUMBER`	Database object number of the block that the buffer represents
`TS#`	`NUMBER`	Tablespace number of block

See Also:
Oracle8i Parallel Server Concepts.