ORACLE V$LOG

我会带着你远行 2023-10-18 23:43 90阅读 0赞

## V$LOG ##

`V$LOG` displays log file information from the control file.

<table> 
 <thead> 
  <tr> 
   <th>Column</th> 
   <th>Datatype</th> 
   <th>Description</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td><code>GROUP#</code></td> 
   <td><code>NUMBER</code></td> 
   <td>Log group number</td> 
  </tr> 
  <tr> 
   <td><code>THREAD#</code></td> 
   <td><code>NUMBER</code></td> 
   <td>Log thread number</td> 
  </tr> 
  <tr> 
   <td><code>SEQUENCE#</code></td> 
   <td><code>NUMBER</code></td> 
   <td>Log sequence number</td> 
  </tr> 
  <tr> 
   <td><code>BYTES</code></td> 
   <td><code>NUMBER</code></td> 
   <td>Size of the log (in bytes)</td> 
  </tr> 
  <tr> 
   <td><code>MEMBERS</code></td> 
   <td><code>NUMBER</code></td> 
   <td>Number of members in the log group</td> 
  </tr> 
  <tr> 
   <td><code>ARCHIVED</code></td> 
   <td><code>VARCHAR2(3)</code></td> 
   <td>Archive status (<code>YES</code>&nbsp;or&nbsp;<code>NO</code>)</td> 
  </tr> 
  <tr> 
   <td><code>STATUS</code></td> 
   <td><code>VARCHAR2(16)</code></td> 
   <td>Log status: 
    <ul> 
     <li> <p><code>UNUSED</code>&nbsp;- Online redo log has never been written to. This is the state of a redo log that was just added, or just after a&nbsp;<code>RESETLOGS</code>, when it is not the current redo log.</p> </li> 
     <li> <p><code>CURRENT</code>&nbsp;- Current redo log. This implies that the redo log is active. The redo log could be open or closed.</p> </li> 
     <li> <p><code>ACTIVE</code>&nbsp;- Log is active but is not the current log. It is needed for crash recovery. It may be in use for block recovery. It may or may not be archived.</p> </li> 
     <li> <p><code>CLEARING</code>&nbsp;- Log is being re-created as an empty log after an&nbsp;<code>ALTER DATABASE CLEAR LOGFILE</code>&nbsp;statement. After the log is cleared, the status changes to&nbsp;<code>UNUSED</code>.</p> </li> 
     <li> <p><code>CLEARING_CURRENT</code>&nbsp;- Current log is being cleared of a closed thread. The log can stay in this status if there is some failure in the switch such as an I/O error writing the new log header.</p> </li> 
     <li> <p><code>INACTIVE</code>&nbsp;- Log is no longer needed for instance recovery. It may be in use for media recovery. It might or might not be archived.</p> </li> 
    </ul></td> 
  </tr> 
  <tr> 
   <td><code>FIRST_CHANGE#</code></td> 
   <td><code>NUMBER</code></td> 
   <td>Lowest system change number (SCN) in the log</td> 
  </tr> 
  <tr> 
   <td><code>FIRST_TIME</code></td> 
   <td><code>DATE</code></td> 
   <td>Time of the first SCN in the log</td> 
  </tr> 
 </tbody> 
</table>