Job logs

A job log contains information related to requests entered for a job. A job log has two forms, a pending form and a spooled form.

In its pending form, a job log for a completed job can change as other jobs (the subsystem, the system operator, and so on) interact with the completed job. In its spooled form, a job log is a snapshot (a moment in time) and does not change (such as spooled files that are created by the Display Job Log (DSPJOBLOG) command, or created after the job completes its activity).

Each job has an associated job log that can contain the following information for the job:

At the end of the job, the job log can be written to the spooled file QPJOBLOG so that it can be printed. However, producing a job log doesn't necessarily mean printing it or creating a spooled file. (For example, the Control Job Log QMHCTLJL API can be used to specify that the job log is to be written to an outfile at the end of job.)

You can reduce the number of job logs produced and reduce the contention for resources (such as output queues). This reduces the resource consumption caused by producing job logs.

• How job logs are created
  Release V5R4 brings job logs into the "on demand" world. The job logs are available when needed, but no work is done to produce job logs for which there is no need.
• Job log pending
  The job log pending state has been available for many years. When a job's job log attribute is *PND, no job log is produced. With the release of V5R4 enhancements have been made to both iSeries Navigator and the character-based interface so that you can now control how and under what circumstances the job log for a specific job will be produced.
• Job log server
  Typically the job log server writes a job's job log to a spooled file. You can route the job log to a printer or to an outfile, (if specified to do so by using the QMHCTLJL, Control job log API), however this is not the recommended method for producing job logs.
• Job log characteristics
  The iSeries™ Navigator provides you with a user friendly, easy to read interface from which you can view job logs and the job log's messages. You can also view job logs by using the character based interface.
• Interactive job logs
  The IBM-supplied job descriptions QCTL, QINTER, and QPGMR all have a log level of LOG(4 0 *NOLIST); therefore all messages help text are written to the job log. However, the job logs are not printed if the job ends normally unless you specify *LIST on the SIGNOFF command.
• QHST History Log
  The history (QHST) log consists of a message queue and a physical file known as a log-version. Messages sent to the log message queue are written by the system to the current log-version physical file.
• Spooled files
  A spooled file holds output data until it can be printed. The spooled file collects data from a device until a program or device is able to process the data. A program uses a spooled file as if it were reading from or writing to an actual device. This is input and output spooling.