7.205 V$EVENT_HISTOGRAM

V$EVENT_HISTOGRAM displays a histogram of the number of waits, the maximum wait, and total wait time on an event basis, in milliseconds. The histogram has buckets of time intervals from < 1 ms, < 2 ms, < 4 ms, < 8 ms, ... < 221 ms, < 222 ms, and >= 222 ms.

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_MILLI

NUMBER

Amount of time the bucket represents (in milliseconds). 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

See Also:

"TIMED_STATISTICS"