Delete、truncate测试

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 This column is obsolete and maintained for backward compatibility.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Always set to N. This column is obsolete and maintained for backward compatibility.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

 

源文档 <http://docs.oracle.com/cd/B19306_01/server.102/b14237/dynviews_1051.htm#REFRN30029>

 

创建时间:2022-03-30 21:10
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