Job monitor

You access the IBM® InfoSphere® DataStage® job monitor through the InfoSphere DataStage Director (see InfoSphere DataStage Director Client Guide). You can also use certain dsjob commands from the command line to access monitoring functions (see Retrieving information for details).

The job monitor provides a useful snapshot of a job's performance at a moment of execution, but does not provide thorough performance metrics. That is, a job monitor snapshot should not be used in place of a full run of the job, or a run with a sample set of data. Due to buffering and to some job semantics, a snapshot image of the flow might not be a representative sample of the performance over the course of the entire job.

The CPU summary information provided by the job monitor is useful as a first approximation of where time is being spent in the flow. However, it does not include any sorts or similar that might be inserted automatically in a parallel job. For these components, the score dump can be of assistance. See "Score Dumps".

A worst-case scenario occurs when a job flow reads from a data set, and passes immediately to a sort on a link. The job will appear to hang, when, in fact, rows are being read from the data set and passed to the sort.

The operation of the job monitor is controlled by two environment variables: APT_MONITOR_TIME and APT_MONITOR_SIZE. By default the job monitor takes a snapshot every five seconds. You can alter the time interval by changing the value of APT_MONITOR_TIME, or you can have the monitor generate a new snapshot every so-many rows by following this procedure:

1. Select APT_MONITOR_TIME on the InfoSphere DataStage Administrator environment variable dialog box, and press the set to default button.
2. Select APT_MONITOR_SIZE and set the required number of rows as the value for this variable.