Oracle教程 2023-02-24

Oracle 视图 DBA_HIST_OSSTAT 官方解释，作用，如何使用详细说明

这个视图

Oracle提供了一个名为DBA_HIST_OSSTAT的视图，它可以显示历史操作系统状态特性。它可以用来评估操作系统亢余资源，并且可以识别任何操作系统异常行为，如负载增加或内存利用率过高。这个视图非常有用，因为它提供的监控信息可以用来监控操作系统性能，并及早发现性能问题。

使用DBA_HIST_OSSTAT视图的方法很简单，只需要补全所有视图列并且指定任何查询约束即可：

SELECT * FROM DBA_HIST_OSSTAT WHERE SNAP_ID IN (‘YYYYMMDDHH24MI’,’YYYYMMDDHH24MI’);

可以用来确定指定快照ID之间，操作系统运行时状态变化：

SELECT OS_STAT_NAME, SNAP_ID, VALUE FROM DBA_HIST_OSSTAT WHERE SNAP_ID IN (‘YYYYMMDDHH24MI’,’YYYYMMDDHH24MI’) AND OS_STAT_NAME = ‘%iowait’;

DBA_HIST_OSSTAT displays historical operating system statistics.

This view contains snapshots of V$OSSTAT.

Column	Datatype	NULL	Description
`SNAP_ID`	`NUMBER`	`NOT NULL`	Unique snapshot ID
`DBID`	`NUMBER`	`NOT NULL`	Database ID for the snapshot
`INSTANCE_NUMBER`	`NUMBER`	`NOT NULL`	Instance number for the snapshot
`STAT_ID`	`NUMBER`	`NOT NULL`	Statistic ID
`STAT_NAME`	`VARCHAR2(64)`	`NOT NULL`	Statistic name
`VALUE`	`NUMBER`		Statistic value
`CON_DBID`	`NUMBER`		The database ID of the PDB for the sampled session
`CON_ID`	`NUMBER`		The ID of the container that `CON_DBID` identifies. Possible values include: `0`: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs. `1`: This value is used for rows containing data that pertain to only the root n: Where n is the applicable container ID for the rows containing data