8.79 V$MUTEX_SLEEP_HISTORY

V$MUTEX_SLEEP_HISTORY displays time-series data. Each row in this view is for a specific time, mutex type, location, requesting session and blocking session combination. That is, it shows data related to a specific session (requesting session) that slept while requesting a specific mutex type and location, because it was being held by a specific blocking session. The data in this view is contained within a circular buffer, with the most recent sleeps shown.

Column Datatype Description

MUTEX_IDENTIFIER

NUMBER

Mutex ID

SLEEP_TIMESTAMP

TIMESTAMP(6)

The last date/time this MUTEX_TYPE and LOCATION was slept for by the REQUESTING_SESSION, while being held by the BLOCKING_SESSION.

MUTEX_TYPE

VARCHAR2(32)

Type of action/object the mutex protects

GETS

NUMBER

The total number of gets since the mutex was created and up until the time of the wait (and from all sessions past and present)

SLEEPS

NUMBER

The number of times the requester had to sleep before obtaining the mutex

REQUESTING_SESSION

NUMBER

The SID of a session requesting the mutex

BLOCKING_SESSION

NUMBER

The SID of a session holding the mutex

LOCATION

VARCHAR2(40)

The code location where the waiter slept for the mutex

MUTEX_VALUE

RAW(4 | 8)

If the mutex is held in exclusive (X) mode, this column shows the SID of the blocking session, else it shows the number of sessions referencing the mutex in S mode.

P1

NUMBER

Reserved for internal use

P1RAW

RAW(4 | 8)

Reserved for internal use

P2

NUMBER

Reserved for internal use

P3

NUMBER

Reserved for internal use

P4

NUMBER

Reserved for internal use

P5

VARCHAR2(64)

Reserved for internal use

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