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Oracle® Database Reference 10g Release 2 (10.2) Part Number B14237-02 |
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# 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
--- | --- | ---
`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 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.
`SLEEPS` | `NUMBER` | The number of times the requestor 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)` | 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` | Internal use only
`P1RAW` | `RAW(4)` | Internal use only
`P2` | `NUMBER` | Internal use only
`P3` | `NUMBER` | Internal use only
`P4` | `NUMBER` | Internal use only
`P5` | `VARCHAR2(64)` | Internal use only