It looks to me like a simple bug with wait event ID 215 and its reporting.
Running a concurrent read from disk test where the number of concurrent threads > number of engine threads (only to increase the frequency of hitting 215), its clear that monProcessWaits only ever reports a single wait event when it does capture it (regardless of the sample interval). However the WaitTime it reports only ever increases (as if it were actually hitting way more wait events).
This is running 3 processes against 2 engine threads
monSysWaits shows what appear to be accurate figures.
| SPID InstanceID | KPID ServerUserID OrigServerUserID WaitEventID | Waits | WaitTime |
----------- ---------- ----------- ------------ ---------------- ----------- ----------- -----------
| 1 | 0 | 9502793 | 1 | 0 | 29 | 38878 | 1128 | |
| 1 | 0 | 9502793 | 1 | 0 | 124 | 27614 | 86437 | |
| 29 | 0 | 9764939 | 1 | 0 | 29 | 42098 | 1166 | |
| 29 | 0 | 9764939 | 1 | 0 | 124 | 27729 | 94387 | |
| 29 | 0 | 9764939 | 1 | 0 | 215 | 1 | 72810 | |
| 36 | 0 | 9633866 | 1 | 0 | 29 | 39516 | 1140 | |
| 36 | 0 | 9633866 | 1 | 0 | 124 | 26901 | 91411 |
(7 rows)
monSysWaits
| InstanceID WaitEventID | WaitTime | Waits |
---------- ----------- ----------- -----------
| 0 | 29 | 4 | 139741 | |
| 0 | 215 | 829 | 502102 |
(2 rows)
A few minutes later:
| SPID InstanceID | KPID ServerUserID OrigServerUserID WaitEventID | Waits | WaitTime |
----------- ---------- ----------- ------------ ---------------- ----------- ----------- -----------
| 1 | 0 | 9502793 | 1 | 0 | 29 | 44196 | 1320 | |
| 1 | 0 | 9502793 | 1 | 0 | 124 | 33502 | 99869 | |
| 1 | 0 | 9502793 | 1 | 0 | 215 | 1 | 86059 | |
| 29 | 0 | 9764939 | 1 | 0 | 29 | 48452 | 1390 | |
| 29 | 0 | 9764939 | 1 | 0 | 124 | 33764 | 107476 | |
| 29 | 0 | 9764939 | 1 | 0 | 215 | 1 | 93007 | |
| 36 | 0 | 9633866 | 1 | 0 | 29 | 44488 | 1311 | |
| 36 | 0 | 9633866 | 1 | 0 | 124 | 32578 | 105050 | |
| 36 | 0 | 9633866 | 1 | 0 | 215 | 1 | 80815 |
(9 rows)
monSysWaits
| InstanceID WaitEventID | WaitTime | Waits |
---------- ----------- ----------- -----------
| 0 | 29 | 4 | 156385 | |
| 0 | 215 | 971 | 536910 |
I'll log this with SAP today and post the CR here.
Cheers,
Simon