Quick Tip: BRF+ trace in TM conditions troubleshooting

[DominikTylczyn]

Photo by Andrea Piacquadio

Conditions are used in several different areas of TM, e.g. freight unit building rule determination, incompatibilities, change strategy determination etc. They are one of the features that makes TM so flexible. However complex conditions might prove challenging to troubleshoot. As TM conditions use BRF+ framework under the hood, BRF+ trace is an essential tool to diagnose them. 

BRF+ trace is activated with the parameter ID /SCMTMS/COND_EXPL = X in the SU3 transaction, the "Parameters" tab. That works beautifully, however there is a catch.

The note 1952185 - Performance improvement in condition processing: Buffering of BRFplus results has introduced TM conditions buffering that improves their performance. The note 1968935 - Activates the new Condition Buffer by standard has activated the buffer by default. 

Now, it can happen that a condition is correctly evaluated, but the BRF+ trace is not saved. That creates a false impression as if the condition has not be evaluated. To make sure that the trace is always saved, the buffering needs to be switched off. That can be done with another parameter ID /SCMTMS/COND_BUF = N.

Make sure to switch the buffering off only for testing, not to detriment production system performance.

The buffering side effect of BRF+ trace not being saved is not really documented explicitly. Thus, I am sharing this tip, so you do not stumble over that as I have recently.

[DominikTylczyn]

SAP has released a KBA about that: 3581783 - Change Controller Determination Strategy is not called on subsequent predecessor document ...