Problem determination optional work area trace

If you suspect an error in the OPEN/CLOSE/EOV component and you can recreate the problem, you can create an optional work area trace to help with diagnosis. The work area trace traces the DCB and the O/C/EOV work area and extended work area associated with the DCB. It also includes a record of the address of the WTG table and the address of the current entry in the WTG table after each O/C/EOV module executes.

To request the optional work area trace, use one of these methods:

Specify DCB=DIAGNS=TRACE on the DD statement of a data set for which you wish to trace
Specify the DALDIAGN text unit with dynamic allocation for a data set for which you wish to trace
Use the problem determination optional work area trace started task, IFGOCETR. Refer to Non-VSAM problem determination work area trace started task for information on the started task. Each time that IFG019RA is entered, it writes the work area and control blocks to the GTF data set. No tracing is done when control is passed to the O/C/EOV problem determination and recovery routines or the initial and final modules of each function of O/C/EOV. Tracing also occurs during access method executor processing for the SAM, BDAM create and BPAM executors.
If you start GTF, use the TRACE=USR option. Refer to Abend error recording initiated by O/C/EOV for more information.

Any of these methods of requesting an optional work area trace causes the BAM component to create an internal BAM trace table. This tracing does not require GTF. Tracing is in a wrap-around trace table. It does not greatly increase execution time and does not produce a great deal of output. Refer to BAM internal trace facility for more information.

Figure 1 shows the GTF output resulting from activating the optional work area trace. In this example, the Open routines abnormally terminated the task because the format-1 DSCB for the data set could not be found. The associated system and return codes are 213-04. The trace record in Figure 1 includes a copy of the DCB, a copy of the O/C/EOV main work area associated with the DCB, various fields from the main work area, and the WTG table. This record will appear several times in the GTF output, once each time an Open object module has been given control.

Because the optional work area trace increases execution time considerably and produces copious output, it should be used only when other diagnostic techniques fail.