Using WebSphere MQ for iSeries trace

Although we need to use certain traces on occasion, running the trace facility slows your systems.

You also need to consider to what destination you want your trace information sent.

Notes:

1. To run the WebSphere MQ for iSeries trace commands, have the appropriate authority.

2. Trace data is written to IFS only when trace is ended, with option *OFF.

3. Trace data remains in the system until you delete it from the IFS.

 

Trace usage

There are two stages in using trace:

1. Decide whether you want early tracing. Early tracing lets you trace the creation and startup of queue managers. Note, however, that early trace can easily generate large amounts of trace, because it is implemented by tracing all jobs for all queue managers. To enable early tracing, use TRCMQM with the TRCEARLY parameter set to *YES.

2. Start tracing WebSphere MQ work using

   TRCMQM *ON. To stop the trace, you have two options:

   • TRCMQM *OFF, to stop collecting trace records for a queue manager. The trace records are written to files in the

     /QIBM/UserData/mqm/trace directory.

   • TRCMQM *END, to stop collecting trace records for all queue managers and to disable early trace. This option ignores the value of the TRCEARLY parameter.

We can also specify the level of detail you want, using the TRCLEVEL parameter set to:

*DFT

For minimum-detail level for flow processing trace points.

*DETAIL

For high-detail level for flow processing trace points.

*PARMS

For default-detail level for flow processing trace points.

 

Selective trace

We can reduce the amount of trace data being saved, improving run-time performance, using the command

TRCMQM with F4=prompt, then

F9 to customize the TRCTYPE and EXCLUDE parameters:

TRCTYPE

Specifies the type of trace data to store in the trace file. If you omit this parameter, all trace points except those specified in EXCLUDE are enabled.

EXCLUDE

Specifies the type of trace data to omit from the trace file. If you omit this parameter, all trace points specified in TRCTYPE are enabled.

The options available on both TRCTYPE and EXCLUDE are:

*ALL (TRCTYPE only)

All the trace data as specified by the following keywords is stored in the trace file.

trace-type-list

We can specify more than one option from the following keywords, but each option can appear only once.

*API

Output data for trace points associated with the MQI and major queue manager components.

*CMTRY

Output data for trace points associated with comments in the WebSphere MQ components.

*COMMS

Output data for trace points associated with data flowing over communications networks.

*CSDATA

Output data for trace points associated with internal data buffers in common services.

*CSFLOW

Output data for trace points associated with processing flow in common services.

*LQMDATA

Output data for trace points associated with internal data buffers in the local queue manager.

*LQMFLOW

Output data for trace points associated with processing flow in the local queue manager.

*OTHDATA

Output data for trace points associated with internal data buffers in other components.

*OTHFLOW

Output data for trace points associated with processing flow in other components.

*RMTDATA

Output data for trace points associated with internal data buffers in the communications component.

*RMTFLOW

Output data for trace points associated with processing flow in the communications component.

*SVCDATA

Output data for trace points associated with internal data buffers in the service component.

*SVCFLOW

Output data for trace points associated with processing flow in the service component.

*VSNDATA

Output data for trace points associated with the version of WebSphere MQ running.

 

Wrapping trace

Use the MAXSTG parameter to wrap trace, and to specify the maximum size of storage to be used for the collected trace records. The options are:

*DFT

Trace wrapping is not enabled. For each job, trace data is written to a file with the suffix .TRC until tracing is stopped.

maximum-K-bytes

Trace wrapping is enabled. When the trace file reaches its maximum size, it is renamed with the suffix .TRS, and a new trace file with suffix .TRC is opened. Any existing .TRS file is deleted. Specify a value in the range 1 through 16 000.