Writing to external data sets

To write to an external data set, you must set EXTERNAL=YES on the TRCLEV statement and specify the EXTTRACE parameter in the BPE configuration parameter member.

1. Define the external trace data set Generation Data Group (GDG).
2. Define the GDG model.
3. Specify the EXTTRACE parameter in the BPE configuration parameter member (BPECFG=) of the IMS.PROCLIB data set. The EXTTRACE statement should specify the name of the GDG you defined in step 1.
4. Specify which trace tables you want to write to the BPE external trace data sets. You can do this by using either or both of the following methods:
   • Include the EXTERNAL=YES parameter with the other TRCLEV options on the TRCLEV statements for the trace tables you want to externalize. The TRCLEV statements are coded in the BPE configuration parameter member (BPECFG=) of the IMS PROCLIB data set.
     Tip: Changes to TRCLEV statements are only processed when an address space is started. If your address space is running when you make the changes, they will not take effect until the address space is restarted.
   • Issue the UPDATE TRACETABLE command, specifying the trace tables you want to externalize on the NAME parameter, and specifying EXTERNAL(YES). This command is used while an address space is running to dynamically turn external tracing on, regardless of the TRCLEV parameter specification.
5. Optional: If you want to start tracing to external data sets but you did not specify the EXTTRACE parameter when you started the address space:
   1. Add the EXTTRACE data set to the BPE configuration member of the IMS.PROCLIB data set while the address space is running.
   2. Issue the UPDATE TRACETABLE command and specify the OPTION(REREAD) option to cause the BPE to process the newly-updated EXTTRACE parameter.