Starting and stopping the GTF

On z/OS®, you can use the generalized trace facility (GTF) to record and diagnose system and program problems.

About this task

You can obtain information about MQI calls and user parameters passed by some IBM® MQ calls on entry to, and exit from, IBM MQ. To do this, use the global trace in conjunction with the z/OS generalized trace facility (GTF).

Procedure

Start the GTF at the console by entering a START GTF command.
When you start the GTF, specify the USRP option. You are prompted to enter a list of event identifiers (EIDs). The EIDs used by IBM MQ are:

5E9

To collect information about control blocks on entry to IBM MQ

5EA

To collect information about control blocks on exit from IBM MQ

Sometimes, if an error occurs that you cannot solve yourself, you might be asked by your IBM support center to supply other, internal, trace information for them to analyze. The additional type of trace is:

5EE

To collect information internal to IBM MQ
You can also use the JOBNAMEP option, specifying the batch, CICS®, IMS, or TSO job name, to limit the trace output to specific jobs. The following example shows a sample startup for the GTF, specifying the four EIDs, and a jobname. The lines shown in bold are the commands that you enter at the console; the other lines are prompts and responses. For more information about starting the GTF trace, see Starting GTF.
```
START GTFxx.yy
 #HASP100 GTFxx.yy ON STCINRDR
 #HASP373 GTFxx.yy STARTED
*01 AHL100A SPECIFY TRACE OPTIONS
R 01,TRACE=JOBNAMEP,USRP
 TRACE=JOBNAMEP,USRP
 IEE600I REPLY TO 01 IS;TRACE=JOBNAMEP,USRP
*02 ALH101A SPECIFY TRACE EVENT KEYWORDS - JOBNAME=,USR=
R 02,JOBNAME=(xxxxMSTR,xxxxCHIN,zzzzzzzz),USR=(5E9,5EA,5EE)
 JOBNAME=(xxxxMSTR,xxxxCHIN,zzzzzzzz),USR=(5E9,5EA,5EE)
 IEE600I REPLY TO 02 IS;JOBNAME=(xxxxMSTR,xxxxCHIN,zzzzzzzz),USR=(5E9,5EA,5EE)
*03 ALH102A CONTINUE TRACE DEFINITION OR REPLY END
R 03,END
 END
 IEE600I REPLY TO 03 IS;END
 AHL103I TRACE OPTIONS SELECTED-USR=(5E9,5EA,5EE)
 AHL103I JOBNAME=(xxxxMSTR,xxxxCHIN,zzzzzzzz)
*04 AHL125A RESPECIFY TRACE OPTIONS OR REPLY U
R 04,U
 U
 IEE600I REPLY TO 04 IS;U
 AHL031I GTF INITIALIZATION COMPLETE
```
where
- xx is the name of the GTF procedure to use (optional)
- yy is an identifier for this occurrence of GTF trace
- xxxx is the name of the queue manager
- zzzzzzzz is a batch job or CICS region name
Up to 5 job names can be listed.
When using GTF, specify the primary job name (CHINIT, CICS, or batch) in addition to the queue manager name (xxxxMSTR).
Stop the GTF at the console.
When you enter the stop command for the GTF, include the additional identifier (yy) that you used at startup, as shown in the following example:
```
 STOP yy
```