DB2 UDB for z/OS Version 8 Performance Topics - IBM Redbooks

3.10.1 Performance
WHEN (NROW.EMPDPTID='010')
BEGIN ATOMIC
UPDATE USRT001.DEPTMENT
SET DPTDPTSZ = DPTDPTSZ + 1
WHERE DPTDPTID = NROW.EMPDPTID;
END;
The sample trigger used in the performance measurement has:
► Name: ADD_AFT
► Trigger activated: AFTER the operation
► Operation starting the trigger: INSERT
► Subject table name: USRT001.EMPLOYEE
► New transition variable correlation name: NROW
► Granularity: FOR EACH ROW
► Trigger condition: WHEN (NROW.EMPDPTID='010')
► Trigger body:
BEGIN ATOMIC
UPDATE USRT001.DEPTMENT
SET DPTDPTSZ = DPTDPTSZ + 1
WHERE DPTDPTID = NROW.EMPDPTID;
END;
For more details on triggers, see Chapter 12. Using triggers for active data in the manual DB2
UDB for z/OS Version 8 Application Programming and SQL Guide, SC18-7415.
Performance measurements were made in two cases:
► 100 inserts activated trigger 100 times
► 100 inserts activated trigger 100 times but WHEN condition evaluated to true only once
The invocation of the triggers is via dynamic SQL. The triggers are static SQL.
100 inserts activated trigger 100 times
Figure 3-39 shows SQL and work file activity in V7 and V8 for the same SQL execution.
Chapter 3. SQL performance 87