Global Contention L-Locks

This topic shows detailed information about Accounting - Global Contention L-Locks.

This block provides global contention information for a logical lock (L-lock) at plan level. It shows conflicts on locking requests between different DB2 members of a data sharing group when those members are trying to serialize shared resources.

For formatting reasons, OMEGAMON XE for DB2 PE shows different labels for report and trace. The following example shows both layouts, the report on the left, and the trace layout on the right.

Accounting - Global Contention L-Locks

The field labels shown in the following sample layout of Accounting - Global Contention L-Locks are described in the following section.


Report:                                                          Trace:

GLOBAL       CONTENTION       L-LOCKS  AVERAGE TIME  AV.EVENT    GLOBAL       CONTENTION       L-LOCKS  ELAPSED TIME    EVENTS
-------------------------------------  ------------  --------    -------------------------------------  ------------  --------
L-LOCKS                                    0.003460      2.00    L-LOCKS                                    0.000000         0
 PARENT (DB,TS,TAB,PART)                   0.002406      1.00     PARENT (DB,TS,TAB,PART)                   0.000000         0
 CHILD  (PAGE,ROW)                         0.000000      0.00     CHILD  (PAGE,ROW)                         0.000000         0
 OTHER                                     0.001054      1.00     OTHER                                     0.000000         0

L-LOCKS - AVERAGE TIME/ELAPSED TIME

The accumulated global contention wait time for all L-locks.

Field Name: ADLKSUST

L-LOCKS - AV.EVENT/EVENTS

The number of global contention waits for all L-locks.

Field Name: ADLKSUSC

PARENT (DB,TS,TAB,PART) - AVERAGE TIME/ELAPSED TIME

The accumulated global contention wait time for parent L-locks.

A parent L-lock can be one of the following types:

Database
Tablespace
Table
Partition

Background and Tuning Information

Performance Expert might adjust this value if the thread was suspended when performance data was gathered.

Field Name: QWACAWTJ

PARENT (DB,TS,TAB,PART) - AV.EVENT/EVENTS

The number of global contention wait events for parent L-locks.

Field Name: ADLPSUSC

CHILD (PAGE,ROW) - AVERAGE TIME/ELAPSED TIME

The accumulated global contention wait time for child L-locks.

A child L-lock type can be:

Page
Row

Field Name: QWACAWTK

CHILD (PAGE,ROW) - AV.EVENT/EVENTS

The number of global contention wait events for child L-locks.

Field Name: ADLCSUSC

OTHER - AVERAGE TIME/ELAPSED TIME

The accumulated global contention wait time for other L-locks. Global extend lock is acquired in exclusive mode by Inserters before an extend service task switch.

Field Name: QWACAWTM

OTHER - AV.EVENT/EVENTS

The number of global contention wait events for other L-locks.

Field Name: ADLOSUSC