Troubleshooting › Diagnose Resource Usage Problems

Diagnose Resource Usage Problems

This section describes problems that you may encounter with resource use.

CPU Usage

Symptoms

An address space uses what you consider to be too much CPU.

Possible Causes

The DBMS has the largest CPU requirements of all of the ReportCenter components.

DBMS and database tuning are specialist and complex topics. Technical Support will provide a plan and work with you to assess and reduce the resource resources of your overall ReportCenter environment.

When you contact Technical Support about any CPU usage problem, please provide answers to the following:

• Is the CPU usage only high when you are viewing large reports? If so, you may be missing some essential APARs in this area.
• What specific metric are you looking at? CPU seconds? CPU%? MIPS?
• What tool are you using to monitor CPU?
• Over what timeframe? How long have you been monitoring?
• What may be a more acceptable range of values?
• When is the CPU thought to be too high? Is there an hourly or daily pattern to the CPU usage? Spikes? When? Long periods of high usage? When? If possible, provide a report of the CPU usage over a period of at least a few days.
• Has ReportCenter always used this amount of CPU, or is it growing?
• Do you have an extremely large database? For example, while different sites have different requirements, fact tables with tens of millions of rows is considered extremely large.

  Use the REPTEST DB command from OCS, to list the database table sizes as at the last Java Task restart.

• How powerful is this LPAR?
• Do you have any Strobe or similar application monitor reports?

JVM Heap Storage

Symptoms

Related error messages in STDERR or STDOUT, possible task termination.

Related error messages in Java Task log.

Related error messages on generated report output page.

Possible Causes

Insufficient JVM heap size specified by the Java Task.

Insufficient LE buffer or storage allocations. Much JVM storage is allocated from LE storage.

JVM incorrectly freeing or reusing storage.

Action

• Check the generated Adaptor.bat HFS file. This shows the initial and maximum heap size specifications on the Java command. These are specified as -ms?M and -mx?M.
• Check the WRCALL23 TASKNAME JVM Memory In Use … messages from the NM Activity log, for the 24 hours immediately preceeding the problem. These messages are issued every 30 minutes; there will be only 48.

  You can change the initial and maximum JVM heap sizes used by the ReportCenter Java Task by updating the ReportCenter Customizer parameter group. The default maximum is 256 MB.

  z/OS Java storage usage and garbage collection is a complex area, much affected by environmental factors. Only change the default values on the recommendation of your systems programming or tuning staff.