Oracle 视图 V$SYS_TIME_MODEL 官方解释，作用，如何使用详细说明
本站中文解释
Oracle视图V$SYS_TIME_MODEL是一个系统模式视图，它报告介绍了系统运行时各种任务的计时信息。
它的列包括： STAT_ID：特定的统计标识符；STAT_NAME：统计的名字；
；VALUE：时间的值；AVERAGE：均值；ELAPSED_TIME：持续的时间；ELAPSED_TIME_DELTA：持续的时间的变化；TIME_WAITED：等待的时间；SESSION_ID：会话标识符；WAITS：统计信息的等待数量。
这个视图主要用于进行性能跟踪，它可以帮助DBA来评估系统的运行状态，看看哪些组件等待的时间最长。
使用方法：
获取性能数据：
SELECT * FROM V$SYS_TIME_MODEL WHERE STAT_NAME = ‘DB time’;
查看系统中每个会话的等待时间：
SELECT SESSION_ID, STAT_NAME, TIME_WAITED FROM V$SYS_TIME_MODEL WHERE stat_name LIKE ‘%wait time’;
官方英文解释
V$SYS_TIME_MODEL displays the system-wide accumulated times for various operations. The time reported is the total elapsed or CPU time (in microseconds). Any timed operation will buffer at most 5 seconds of time data. Specifically, this means that if a timed operation (such as SQL execution) takes a long period of time to perform, the data published to this view is at most missing 5 seconds of the time accumulated for the operation.
The time values are 8-byte integers and can therefore hold approximately 580,000 years worth of time before wrapping. Background process time is not included in a statistic value unless the statistic is specifically for background processes.
| Column | Datatype | Description |
|---|---|---|
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Statistic identifier for the time statistic |
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Name of the statistic (see Table 10-1) |
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Amount of time (in microseconds) that the system has spent in this operation |
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The ID of the container to which the data pertains. Possible values include:
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Note:
This view returns instance-wide data and a value of 0 in the CON_ID column when queried from the root of a CDB.
