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Oracle 视图 V$EVENT_HISTOGRAM_MICRO 官方解释，作用，如何使用详细说明

本站中文解释

Oracle中的视图V$EVENT_HISTOGRAM_MICRO提供了系统事件处理时间的柱状图。该视图可以帮助DBA确定系统性能问题并根据每个事件的处理时间来识别性能瓶颈。查询这个视图时，信息将以快照形式显示，按照快照的时间点显示每个事件的相关信息，包括视频柱状图，事件中的处理时间等。

使用方法：

为查询此视图，可以使用以下查询语句：

SELECT EVENT_ID, TIME_WAITED_MICRO, WAIT_COUNT, AVERAGE_WAIT, RATE, HISTOGRAM
FROM V$EVENT_HISTOGRAM_MICRO;

该查询将给出每个事件的相关信息，如该事件的ID，处理时间，次数，平均等待时间，频率以及柱状图。可以通过这些信息了解系统中不同事件的性能状况，从而帮助确定瓶颈所在。

官方英文解释

V$EVENT_HISTOGRAM_MICRO displays a histogram of the number of waits, the maximum wait, and total wait time on an event basis, in microseconds. The histogram has buckets of time intervals from < 1 us, < 2 us, < 4 us, < 8 us, … < 231 us, < 232 us, and >= 232 us.

The histogram will not be filled unless the TIMED_STATISTICS initialization parameter is set to true.

Column Datatype Description

EVENT#

NUMBER

Event number

EVENT

VARCHAR2(64)

Name of the event

WAIT_TIME_FORMAT

VARCHAR2(30)

A human readable time string which is converted from WAIT_TIME_MICRO. When WAIT_TIME_MICRO < 1 millisecond, WAIT_TIME_FORMAT is shown in microseconds. When WAIT_TIME_MICRO < 1 second, WAIT_TIME_FORMAT is shown in milliseconds. When WAIT_TIME_MICRO < 1 minute, WAIT_TIME_FORMAT is shown in seconds. When WAIT_TIME_MICRO > 1 minute, WAIT_TIME_FORMAT is shown in minutes and seconds.

WAIT_TIME_MICRO

NUMBER

Amount of time the bucket represents (in microseconds). If the duration = num, then this column represents waits of duration < num that are not included in any smaller bucket.

WAIT_COUNT

NUMBER

Number of waits of the duration belonging to the bucket of the histogram

LAST_UPDATE_TIME

VARCHAR2(64)

Indicates the last time the bucket was updated (the ending timestamp of the last wait falling into the bucket’s duration)

CON_ID

NUMBER

The ID of the container to which the data pertains. 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


数据运维技术 » Oracle 视图 V$EVENT_HISTOGRAM_MICRO 官方解释，作用，如何使用详细说明
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