Thread Global Lock Activity
This panel provides detail information about current locking activity of a selected thread in a data sharing environment.
________________ ZTGLOC VTM O2 V540./I SE11 07/11/13 13:44:32 2
> Help PF1 Back PF3
> THREAD INFORMATION: Enter a selection letter on the top line.
> A-THREAD DETAIL B-LOCK COUNTS C-LOCK WAITS D-LOCKS OWNED *-GLOBAL LOCKS
> F-CURRENT SQL G-SQL COUNTS H-DISTRIBUTED I-BUFFER POOL J-GROUP BP
> K-PACKAGES L-RES LIMIT M-PARALLEL TASKS N-UTILITY O-OBJECTS
> P-CANCEL THREAD Q-DB2 CONSOLE R-DSN ACTIVITY S-APPL TRACE T-ENCLAVE
> U-LONG NAMES W-ACCEL ACTIVITY
===============================================================================
> THREAD GLOBAL LOCK ACTIVITY
PLAN
+ Thread: Plan=DISTSERV Connid=SERVER Corrid=db2jcc_appli Authid=HONG
+ Dist : Type=DATABASE ACCESS, Luwid=G9414CE5.G536.CBA4ADE06FAA=591
+ Location : 9.65.76.229,Host Name=sig-9-65-76-229.mts.ibm.com
gloc
+ P-lock Lock Requests = 0 XES Lock Requests = 2
+ P-lock Unlock Requests = 0 XES Unlock Requests = 0
+ P-lock Change Requests = 0 XES Change Requests = 0
+ Suspends - IRLM Global Cont = 0 Total L-lock Requests = 6
+ Suspends - XES Global Cont = 0 XES L-lock Req Percentage = 66.6%
+ Suspends - False (and Conv) = 0 Incompatible Retained Locks = 0
+ Notify Messages Sent = 0 Total Number False Content. = 0
=============================================================================== Fields
Thread identifier: This information identifies the thread to which
the information in this panel applies.
- Plan
- The Db2 plan name of the active thread.
- Connid
- The Db2 connection identifier of the active thread.
- Corrid
- The Db2 correlation identifier of the active thread. If the correlation is not set, N/A is displayed.
- Authid
- The Db2 authorization identifier of the active thread.
- Attach
- Depending on the type of connection, the appropriate information is displayed.
- Connection Type
-
- Batch
- The MVS jobname and ASID.Note: For threads from remote Db2, the MVS job name is N/A.
- CICS®
- The CICS jobname, task name, task number, terminal ID,
and thread type. The thread type is:
- Pool
- The thread in use is a pool thread.
- Entry
- The thread in use is a nonprotected entry thread.
- Prot
- The thread in use is a protected thread. Protected threads are defined in an RCT entry definition using the THRDS operand.
- IMS
- The IMS region number, transaction name, region name, and terminal ID (LTERM).
- RRSAF
- The MVS job name and ASID.Note: For threads from remote Db2, the MVS job name is N/A.
- System
- The originating Db2 job name and the resource manager that is the source of the thread. An additional line below the Attach line identifies the user thread, if any, being served by the system thread.
- TSO
- The TSO user ID and region ASID.
- Utility
- No additional information.
- Db2
- The Db2 subsystem identifier.
- MVS
- The MVS system identifier.
- ORIGAUTH
- The original (primary) Db2 authorization identifier of the thread. This field displays only when the original identifier is different from the Authid.
Package identifier: This information identifies the package to
which the information in this panel applies.
Distributed thread identifier: The following
fields are displayed if the thread has a distributed relationship with a remote Db2 subsystem.
- Type
- The distributed thread type.
- Distributed Allied
- A requesting thread; one that has issued an SQL call to a remote Db2 location.
- Database Access
- A responding thread; one that is serving a remote Db2 location by responding to an SQL call.
- Db2=
- The Db2 subsystem ID, indicating the member of the data sharing group of this thread.
- Luwid
- This value consists of two parts: the logical unit of work ID (luw-id) and a
token. The token can be used in place of the luw-id in any Db2
command that accepts luw-id as input. Format:
luw-id=tokenThe luw-id consists of the network name, the originating VTAM® LUNAME, and a unique identifier (separated by periods). Thus, the Luwid field displays data like in the following example:
USCACO01.O2D22A.A1FE8E04B9D4=8 - System
- The originating Db2 job name and the resource manager that is the source of the thread. An additional line below the Attach line identifies the user thread, if any, being served by the system thread.
Global lock information:
- P-lock Lock Requests
- Number of lock requests for P-locks. A P-lock is a physical lock used only in a data sharing environment to provide consistency of data cached in different Db2 subsystems.
- P-lock Unlock Requests
- Number of unlock requests for P-locks.
- P-lock Change Requests
- Number of change requests for P-locks.
- XES Lock Requests
- The number of lock requests (both logical and physical) that were 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 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 Change Requests
- The number of change requests (both logical and physical) that were propagated to MVS XES synchronously under the caller's execution unit. This count does not include suspended requests.
- Suspends - IRLM Global Cont
- 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 Cont
- 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 (and Conv)
- Summation of false contentions and sync-to-async heuristic conversions.
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.
Sync-to-async heuristic conversions are done when the XES determines that it is more efficient to drive the request asynchronously to the coupling facility.
- Total L-lock Requests
- The total number of L-lock requests. An L-lock is a logical lock used to control intra- and inter-DB2 data concurrency between transactions.
- XES L-lock Req Percentage
- The percentage of total L-lock requests that were propagated to MVS XES synchronously.
- 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.
- Total Number False Content.
- The total number of false contentions for LOCK and UNLOCK requests. A false contention occurs when different resource names hash to the same entry in the coupling facility (CF) lock table. The CF detects contention within the hash entry, and XES uses intersystem messaging to determine that no actual resource contention exists.