Global Lock Statistics
This panel shows information about current global locking activity in a data sharing environment.
________________ ZGLOK VTM O2 V540./C SZ21 DD/MM/YY HH:MM:SS 2
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> A-LOCK STATISTICS *-GLOBAL LOCK STATISTICS H-HISTORICAL
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> GLOBAL LOCK STATISTICS
GLOK
+ Collection Interval: REALTIME Start: 09/10 13:46:49
+ Report Interval: 3 sec End: 09/10 13:47:05
+
+ Total Global Contention = .5% P-Lock/Notify Engines = 500
+ False Contention = .1%
+
+ TOTAL INTERVAL /SECOND /THREAD /COMMIT
+ QUANTITY QUANTITY ( 3) ( 0) ( 0)
+ -------- -------- ------- ------- -------
+ P-Lock Lock Requests 3972 0 .00 .00 .00
+ P-Lock Change Requests 193 0 .00 .00 .00
+ P-Lock Unlock Requests 3386 0 .00 .00 .00
+
+ XES Lock Requests 60530 18 6.00 .00 .00
+ XES Change Requests 7326 0 .00 .00 .00
+ XES Unlock Requests 60764 18 6.00 .00 .00
+ XES Asynchronous Requests 28 0 .00 .00 .00
+ XES Sync to Async Conv 8928 9 .04 3.00 .03
+
+ Suspends-IRLM Global Contention 452 0 .00 .00 .00
+ Suspends-XES Global Contention 0 0 .00 .00 .00
+ Suspends-False Contention 162 0 .00 .00 .00
+
+ Negotiate Pageset P-Locks 82 0 .00 .00 .00
+ Negotiate Page P-Locks 0 0 .00 .00 .00
+ Negotiate Other P-Locks 62 0 .00 .00 .00
+ Negotiate P-Lock Change 128 0 .00 .00 .00
+
+ Incompatible Retained Locks 0 0 .00 .00 .00
+ Notify Messages Sent 719 0 .00 .00 .00
+ Notify Messages Received 942 0 .00 .00 .00
+ Engine Not Available 0 0 .00 .00 .00
+ Very Conditional Rejections 0 0 .00 .00 .00
+
+ IRLM SYSTEM ACTIVITY COUNTERS
+ ------------------------------
+ CB Latch Cont. 1198 2 .01 .67 .01
+ Global Deadlocks 0 0 .00 .00 .00
+ Local Resource Cont. 1831 0 .00 .00 .00
+ Global Resource Cont. 10237 9 .04 3.00 .03
+ Cont. Exit Visits 9193 9 .04 3.00 .03
+ False Cont. 1212 1 .00 .33 .00
+ Plock Exit Visits 2221 4 .02 1.33 .01
+ Notify Exit Visits 81892 70 .33 23.33 .23
===============================================================================Navigation
For additional information about:
- Other topics, use the PF keys.
Fields
- Collection Interval
- Shows the
REALTIMEto indicate that you are looking at the realtime version of this panel and not at the corresponding near-term history panel. The collection interval and the report interval are the same in this panel. - Start
- The start time of the interval currently displayed.
- Report Interval
- This field determines the report interval. It is set on the Near-Term History Report Option panel.
- End
- The end time of the interval currently displayed.
- Total Global Contention
- The percent of synchronous XES lock, change, or unlock requests that resulted in global contention.
- False Contention Percentage
- The rate of false contentions to real contentions. This number should be no more than 50%.
- P-Lock/Notify Engines
- The number of engines available for P-lock exit or notify exit requests.
For each of the following fields, the
following statistics values are provided:
- TOTAL QUANTITY
- Total quantity, which reflects the amount of activities since DB2 was started.
- INTERVAL QUANTITY
- Interval quantity, which reflects the amount of activities during the last cycle.
- /SECOND
- Rate per second during the last cycle. The number under /SECOND (in parentheses) is the number of seconds in the interval.
- /THREAD
- Rate per thread during the last cycle. The number under /THREAD (in parentheses) is the number of Create Threads during the interval.
- /COMMIT
- Rate per Commit during the last cycle. The number under /COMMIT (in parentheses) is the number of commit requests (including abort requests) during the interval.
- P-lock Lock Requests
- Number of lock requests for P-locks.
- P-lock Change Requests
- Number of change requests for P-locks.
- P-lock Unlock Requests
- Number of unlock requests for P-locks.
- XES Lock Requests
- The number of lock requests (both logical and physical) that are propagated to MVS XES synchronously under the caller's execution unit. This count does not include suspended requests. Only the most restrictive lock for a particular resource is propagated to XES and the coupling facility.
- XES Change Requests
- The number of change requests (both logical and physical) that are propagated to MVS XES synchronously under the caller's execution unit. This count does not include suspended requests.
- XES Unlock Requests
- The number of unlock requests (both logical and physical) that are propagated to MVS XES synchronously under the caller's execution unit. This count does not include suspended requests.
- XES Asynchronous Requests
- The number of L-locks and P-locks propagated to XES asynchronously. This occurs when a new inter-DB2 interest occurs on a parent resource or when a request completes after the requestor's execution unit has been suspended.
- XES Sync to Async Conv
- The number of sync to async heuristic conversions for LOCK requests in XES. This conversion is done when XES determines that it is more efficient to drive the request asynchronously to the CF.
- Suspends-IRLM Global Contention
- The number of suspends due to Internal Resource Lock Manager (IRLM) global resource contentions. IRLM lock states were in conflict and inter-system communication is required to resolve the conflict.
- Suspends-XES Global Contention
- The number of suspends due to MVS XES global resource contentions that were not IRLM-level contentions. The XES lock states were in conflict, but the IRLM lock states were not.
- Suspends-False Contention
- The number of suspends caused by MVS XES false contentions. XES detects hash class contention when two different locks on different resources hash to the same entry in the coupling facility lock table. The requester is suspended until it is determined that no real lock contention exists.
- Negotiate Pageset P-Locks
- The number of times this Db2 member was driven to negotiate a pageset/partition P-lock because of changing inter-DB2 interest levels on the pageset/partition.
- Negotiate Page P-Locks
- The number of times this Db2 member was driven to negotiate a page P-lock because of inter-DB2 P-lock contention.
- Negotiate Other P-Locks
- The number of times this Db2 member was driven to negotiate a P-lock type other than pageset/partition or page.
- Negotiate P-Lock Change
- The number of times a P-lock change request was issued during P-lock negotiation.
- Incompatible Retained Locks
- The number of global lock or change requests that failed because of an incompatible retained lock. Certain P-locks can be retained because of a system failure. Another DB2 member cannot access the data that the retained P-lock is protecting unless it requests a P-lock in a compatible state.
- Notify Messages Sent
- The number of notify messages sent.
- Notify Messages Received
- The number of notify messages received.
- Engine Not Available
- The number of times an engine was not available for a P-lock exit or a notify exit request.
- Very Conditional Rejections
- The number of rejections of very conditional requests which could not get processed because of the heuristic algorithm used by XES.
IRLM System Activity Counters:
- CB Latch Cont.
- Active IRLM Control Block latch contention counter.
- Global Deadlocks
- Total number of global deadlocks.
- Local Resource Cont.
- Local resource contentions.
- Global Resource Cont.
- Global resource contentions.
- Cont. Exit Visits
- Visits to the contention exit, and IRLM granted the request. How many times lock contention was found and the request was sent to IRLM contention Exit, and the request was granted.
- False Cont.
- False contentions.
- Plock Exit Visits
- Plock Exit counter.
- Notify Exit Visits
- Notify Exit counter.