Oracle 视图 DBA_HIST_ASH_SNAPSHOT 官方解释,作用,如何使用详细说明
本站中文解释
Oracle视图DBA_HIST_ASH_SNAPSHOT存储数据库应用程序自任务跟踪使用的信息,可以帮助DBA以窗口方式查看系统上活动的会话以及其执行的任务的性能。这个视图内的数据基于任务跟踪(AWR)报告的任务快照采样器数据收集的,可以帮助识别会话中正在执行的任务,滚动及重复任务。
使用时,首先要执行oracle脚本dbms_scheduler.create_snapshot来创建任务跟踪快照,采样时间可以根据实际情况进行调整,但不能小于15秒以下,然后查看DBA_HIST_ASH_SNAPSHOT 视图中的数据,根据任务的SQL_ID字段把任务的SQL文件和相关执行结果查询出来,根据这些信息就可以进行性能分析并得出解决方案了。
官方英文解释
DBA_HIST_ASH_SNAPSHOT provides the list of snapshots that contains Active Session History (ASH) data.               
This view differs from DBA_HIST_SNAPSHOT in that it provides snapshots which had errors flushing some Automatic Workload Repository (AWR) tables, but for which ASH data may be successfully flushed (DBA_HIST_SNAPSHOT filters out snapshots which had errors flushing AWR tables).                  
| Column | Datatype | NULL | Description | 
|---|---|---|---|
| 
 | 
 | 
 | Unique snapshot ID | 
| 
 | 
 | 
 | Database ID for the snapshot | 
| 
 | 
 | 
 | Instance number for the snapshot | 
| 
 | 
 | 
 | Startup time of the instance | 
| 
 | 
 | 
 | Time at the beginning of the snapshot interval | 
| 
 | 
 | 
 | Time at the end of the snapshot interval; the actual time the snapshot was taken | 
| 
 | 
 | Amount of time to perform the snapshot | |
| 
 | 
 | Snapshot level | |
| 
 | 
 | Indicates if the snapshot was successfully flushed without any errors. Possible values: 
 | |
| 
 | 
 | Number of errors occurring in the tables for the particular snapshot | |
| 
 | 
 | Reserved for internal use | |
| 
 | 
 | Condition under which the snapshot was inserted. Possible values are: 
 | |
| 
 | 
 | Snapshot time zone expressed as offset from UTC (Coordinated Universal Time) time zone | |
| 
 | 
 | The ID of the container to which the data pertains. Possible values include: 
 | 
See Also:
“DBA_HIST_SNAPSHOT”
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