IDB2 High CPU in Data Collector

Products

• Database Management for DB2 for z/OS - Administration Suite
• Database Management for DB2 for z/OS - Performance Suite
• Database Management for DB2 for z/OS - Recovery Suite
• Database Management for DB2 for z/OS - SQL Performance Suite
• Database Management for DB2 for z/OS - Utilities Suite

Issue/Introduction

Data Collector saw a 10  time increase in CPU usage for a period of time with heavy point-of-sale processing.  This is unusual for  the started task  gobbling up CPU.  Why did the started task use so much CPU? 

 

Environment

Release : 20.0

Resolution

For this case running the batch job against user provided SMF file revealed COLL ID ARGRX1  PROGRAM CP031929 to be the cause of the ZIIP CPU spike. ZIIP spike is probably due to the high volume of thread activity during that period as IDB2  Trace/ History file processing uses ZIIP. There  has been 357 packages executed under one thread with (PLAN NAME: RX1CICS and CORRID:ENTRTNDC0009). So there might be a spike in ZIIP usage during the Trace/ History file processing. Recommended the following steps to see the zIIP utilization

 

1-From the Main Menu, click the T of Tools to get a pull down sub menu

2-Select1 COMMANDS
             

3-Then select 3 SYSVIEW for DB2 Commands

4-Issue ===> DCCPU to generate a report to give you zIIP utilization.