Oracle 视图 V$ROLLSTAT 官方解释，作用，如何使用详细说明
本站中文解释
：
V$ROLLSTAT 视图提供了表面查看逻辑恢复日志这个重要组件的信息，包括日志从上次检查点到现在被应用的情况，是否存在未激活的更改，打开的日志数量，你可以用它来分析你的恢复链是否有效，足够安全，还可以用它来确定你归档和重做日志长度，把它们锁定在合理长度以满足你的业务需求。
使用方法：
1.查询当前逻辑恢复日志中应用和未激活的更改：
SELECT * FROM V$ROLLSTAT;
2.查询当前逻辑恢复日志中开放日志的文件数：
SELECT COUNT(*) FROM V$ROLLSTAT WHERE STATUS=’OPENED’;
官方英文解释
V$ROLLSTAT contains rollback segment statistics.
| Column | Datatype | Description |
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Rollback segment number |
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Latch for the rollback segment |
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Number of extents in the rollback segment |
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Size (in bytes) of the rollback segment. This value differs by the number of bytes in one database block from the value of the See Also: Oracle Database |
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Number of bytes written to the rollback segment |
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Number of active transactions |
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Number of header gets |
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Number of header waits |
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Optimal size of the rollback segment |
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High watermark of the rollback segment size |
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Number of times the size of a rollback segment decreases |
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Number of times rollback segment is wrapped |
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Number of times rollback segment size is extended |
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Average shrink size |
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Current size of active extents, averaged over time. |
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Rollback segment status:
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Current extent |
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Current block |
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The ID of the container to which the data pertains. Possible values include:
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