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.
The last date/time this MUTEX_TYPE and LOCATION was slept for by the REQUESTING_SESSION, while being held by the BLOCKING_SESSION.
Type of action/object the mutex protects
The number of times the mutex/location was requested by the requesting session while being held by the blocking session. GETS is only incremented once per request, irrespective of the number of sleeps required to obtain the mutex.
The number of times the requestor had to sleep before obtaining the mutex
The SID of a session requesting the mutex
The SID of a session holding the mutex
The code location where the waiter slept for the mutex
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.