7.205 V$EVENT_HISTOGRAM_MICRO

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