Formatting and interpreting trace entries

Before you can look at the trace entries that have been sent to the various trace destinations, you need to do some formatting. The way you do the formatting varies depending on the destination.

You can specify abbreviated, short, or full trace formatting, to give you varying levels of information and detail in your output. Typically, abbreviated-format trace gives you one line of trace per entry; short-format provides two lines of trace per entry; full-format provides many lines of trace per entry. The structures of the different types of trace entry are described in the sections that follow.

Most of the time, the abbreviated trace table is the most useful form of trace formatting, as you can quickly scan many trace entries to locate areas of interest.

However, in error situations, you might require more information than the abbreviated trace can provide. The short trace provides the information that is presented in the abbreviated trace, and, additionally, presents certain items that are presented in the full trace. These are:
  • Interpreted parameter list
  • Return address
  • Time that the trace entry was written
  • Time interval between trace entries

These items of information are often very useful in the diagnosis of problems. By selecting the short format, you can gain access to this information without having to bear the processing overhead of formatting a full trace, and without having to deal with the mass of information in a full trace.

There may be occasions, however, when you need to look at full format trace entries, to understand more fully the information given in the corresponding abbreviated and short entries, and to be aware of the additional data supplied with many full trace entries.

For abbreviated and full trace formatting, a trace summary table provides summary information about the trace entries that relate to each task in the system during the time period. The trace summary table appears at the end of the formatted trace output. Use the table to see the tasks that were traced, and the location and number of their trace entries in the trace output. The table also highlights any long time gaps between the trace entries for a task, which can indicate a performance problem, and any exception trace entries for a task. The trace summary table is not produced for short-format trace.

The internal trace table can be formatted in one of two ways:
  1. From a CICS® system dump, using the CICS print dump exit, DFHPD710.
  2. From a transaction dump, using the CICS dump utility program, DFHDU710.

Auxiliary trace can be formatted using the CICS trace utility program, DFHTU710. You can control the formatting, and you can select trace entries on the basis of task, terminal, transaction, time frame, trace point ID (single or range), dispatcher task reference, and task-owning domain. This complements the usefulness of auxiliary trace for capturing large amounts of trace data.

Note: Trace entries can only be formatted selectively by transaction or terminal if the “transaction attach” entry (point ID XM 1102, XM level-1) for the transaction is included in the trace data set. The transaction attach entry will not be written if for example the main system trace flag is switched off and the transaction status is set to special.

GTF trace can be formatted with the same sort of selectivity as auxiliary trace, using a CICS-supplied routine with the MVS™ interactive problem control system (IPCS).

For more details of trace utility programs, see Trace utility print program (DFHTU700).