V$BH
V$BH displays the status and number of pings for every buffer in the SGA. 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 buffer:
|
| 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 This column is obsolete and maintained for backward compatibility.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| NEW | VARCHAR2(1) | Always set to N. This column is obsolete and maintained for backward compatibility.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 |
来自 “ ITPUB博客 ” ，链接：https://blog.itpub.net/563971/viewspace-277782/ ，如需转载，请注明出处，否则将追究法律责任。
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