Locking Conflicts panel

This panel shows existing Db2 locking contentions. It provides information about the owners and waiters currently involved in locking conflicts.

A locking conflict exists when a Db2 thread owning a resource causes another Db2 thread to wait. In general, when Db2 cannot satisfy a request for the resource, the requester will be suspended.

A suspended lock resource always has an owning thread. Multiple threads may be waiting for the same resource. It may also have one or more global owners that have global interest in the resource.

When S mode is used in data sharing environment, lock resources that are waited by a local thread will be displayed. All global owners and all local threads that are involved in this locking conflict are displayed.

When G mode is used in data sharing environment, lock resources that are waited by a local or remote thread will be displayed. All the global owners and all local and remote threads that are involved in the locking conflict are displayed.

The plan names of all threads for which the elapsed time exception has tripped are highlighted. For more information about current thread exceptions, type E.A on the top line of the panel to display the Exception Messages for Thread Exceptions panel.


________________ ZLOCKC   VTM     O2       V550.#P SAD  G 11/05/13 14:00:19 2 
>       Help PF1      Back PF3      Up PF7      Down PF8       Zoom PF11       
> L.                                                                           
===============================================================================
>                             LOCKING CONFLICTS                                
                                                                               
 XLOK                                                                          
+Stat Plan     Corrid       Type Lvl Resource                                  
+---- -------- ------------ ---- --- ------------------------------------------
+Owned by Subsystem SAC     ROW      DB=DSNDB04  PS=RLOCKTSG PG=00000002/01    
+Owned by Subsystem SAD     ROW      DB=DSNDB04  PS=RLOCKTSG PG=00000002/01    
+ OWN DSNESPCS MIS          ROW    X DB=DSNDB04  PS=RLOCKTSG PG=00000002/01    
+WAIT DSNESPCS MIS          ROW    U DB=DSNDB04  PS=RLOCKTSG PG=00000002/01    
===============================================================================

Highlighting

OMEGAMON® for Db2 PE highlights some fields in this panel to draw your attention to their current status:

Table 1. Highlighted fields in Locking Conflicts panel
Field	Exception	Reason
Plan	ETIM	Elapsed time is high.

Navigation

For additional information about:

A lock owner, move the cursor to the lock owner line and press F11 (Zoom).
A lock waiter, move the cursor to the lock waiter line and press F11 (Zoom).
Other topics, use the PF keys.

Note: Thread information is not available if the thread is owned by the other member of the data sharing group.

Fields

The output lines are displayed in descending order, with those reflecting the greatest degree of conflict displayed first.

Stat

The status of the thread can be one of the following:

OWN indicates that the thread is a lock owner.
WAIT indicates that the thread is suspended because the lock it requested is owned by another thread.

Plan

The name of the Db2 plan that is currently active in this thread.

Corrid

The Db2 correlation identifier for the thread involved in the locking conflict.

Type

The type of lock that is owned or requested and is unavailable.

Lvl

The level at which the lock is owned or was requested. The level of a lock requested is frequently the reason for lock suspensions.

Resource

Identifies the resource that is currently locked by the lock owner, or the lock resource causing the lock to be suspended. The resource varies depending upon the type of lock held.

Note: DB=database name can be represented as a DBID=identifier, which is the decimal identifier of the database. PSID=identifier can be represented as PSID=identifier, which is the decimal identifier of the table space. HEX values are displayed for lock resources if the resource is owned by a thread on a remote LPAR, and no OMPE task is available from that LPAR, or XCF is not set up correctly. If the owner is a thread running on some other member of the data sharing group, the Db2 subsystem name is displayed.

This field displays the following resources:

Lock Type: Resource
ACSC: Accelerator Services commands lock
ALBP: Alter buffer pool lock
BIND: Autobind/remote bind lock
BMBA: Buffer manager SCA MBA L-lock
BPPS: Buffer manager pageset RP P-lock
CCAT: CATMAINT convert catalog lock
CDBL: Compress dictionary build lock
CDIR: CATMAINT convert directory lock
CDRN: Cursor Stability drain lock
CMDS: Db2 Command Serialization lock
CMIG: CATMAINT migration lock
COLL: Collection lock
DBEX: Database exception LPL/GRECP lock
DBXU: Database exception update lock
DGTT: DGTT URID lock
DPAG: Db2 pageset page lock
DPLK: 32 K Desperation Pool lock
DSET: Partitioned lock
DTBS: Database lock
GRBP: Group buffer pool start/stop lock
HASH: Hash anchor lock
IEOF: Index end of file lock
IPAG: Index page lock
LBLK: LOB lock
LPLR: LPL Recovery lock
MDEL: Mass delete lock
PALK: Partition lock
PBPC: Group buffer pool castout P-lock
PCDB: DDF CDB P-lock
PDBD: DBD P-lock
PDSO: Pageset or partition pageset open lock
PITR: Index manager tree P-lock
PPAG: Page P-lock
PPSC: Pageset/partition level castout P-lock
PPSP: Pageset/partition P-lock
PRLF: RLF P-lock
PSET: Pageset lock
PSPI: Pageset piece lock
RDBD: Repair DBD Test/Diagnoes lock
RDRN: Repeatable Read drain lock
RGDA: Retry Getpg During Abort
ROW: Row lock
RSTR: SCA access for restart/redo lock
SDBA: Start/stop lock on DBA tabs
SENV: SYSENV serialization lock
SKCT: Skeleton cursor table lock
SKPT: Skeleton package table lock
SPRC: Sys Level PIT Recovery lock
SREC: Log range lock
TABL: Table lock
UIDA: Util I/O Damage Assessment
UNDT: Undetermined lock
UTEX: Utility exclusive execution lock
UTID: Utility UID lock
UTSE: Utility serialization lock
WDRN: Write drain lock
XMLK: XML lock
UTOB: Utility object lock
DBDL: DBD load lock
IXKY: Index key lock
HPSP: Header page bucket or Stored Proc Cmd lock