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CPSM WLM Transaction Routing is not evenly distributed when using QUEUE mode

Troubleshooting


Problem

You added a new CICS system (CICSSYS) to a CICS group (CICSGRP). But, CICSPlex SM workload management (CPSM WLM) routes transactions to the new CICS system more often than the other CICS systems in the CICS group. The workload algorithm type is QUEUE mode.

Cause

The queue algorithm calculated load in the new CICS system is lower than the other target CICS systems. CPSM Monitoring is not active for the new CICS region, thus there are fewer Long Running Tasks (LRTs) for CPSM CONM monitoring transactions running in the new CICS system.

Environment

CICS CICSPlex SM transaction routing

Diagnosing The Problem

When the routing algorithm type is QUEUE mode and all other routing selection criteria is the same, consider the queue load.

The best method of finding out all the factors that are going into the CPSM WLM routing decision making process is to use the WUI EYUSTARTWLMATARG.TABULAR3 view, "Complete active target region details." In that view you can review factors such as WLM routing weight for region, whether the region is dumping, MXT, non-responsive, SOS, and a number of other factors.

It must be noted though, that CPSM does NOT attempt to route work evenly. It routes work to the region that, based on the factors it knows about, will complete the work the quickest. This can lead to uneven distribution, even when all other CPSM viewed factors are equal. This is because other factors outside of CICS may affect a region, such as MVS Dispatching priority or CPU contention.

Resolving The Problem

Activate CPSM Monitoring for the new CICS system for the same CICS resources as the other target regions in the workload AORSCOPE. This will result in an increased CONM task count similar to the task count of the other target CICS systems. Then transaction routing will be more evenly distributed between the target CICS systems.

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Product Synonym

CICSPlex SM CICSPlexSM CPSM CP/SM

Document Information

Modified date:
22 February 2023

UID

swg21182363