What time was that subsystem started?

The question was simple:  Can you tell when a subsystem started?

I am going to give two examples. The first will show what I would do if you asked me what time the QPGMR subsystem was started. I only need to give an answer one time, and I do not need to write a program or code to do this.

In the second example I do want some code to show when the QPGMR subsystem was started. This would be used in a scenario where I would need to know frequently what time it started. I would add it to the Job Scheduler, run the job periodically, and it would send me an email with the date and time it started included within.

 

Example 1: One time

At any command line I would type in:

WRKACTJOB SBS(QPGMR)

The results show all of the active jobs in the QPGMR subsystem. If there are no results the subsystem is not active.

Work with Active Jobs Current Opt Subsystem/Job User Type CPU % Function Status 5 QPGMR QSYS SBS .0 DEQW _ QPADEV0001 SIMON INT .0 CMD-WRKACTJOB DSPW

The first job is the one that is started when the subsystem is started. I put a "5" next to it, as shown, and press Enter.

At the "Work with job menu" I take option 10 for "Display job log, if active, on job queue, or pending".

The first line shown has the date and time when the subsystem was started:

Display Job Log System: DEV740 Job . . : QPGMR User . . : QSYS Number . . . : 110064 Job 110064/QSYS/QPGMR started on 02/22/21 at 09:24:53 in subsystem QPGMR

 

Example 2: Frequently

I can use the information from two SQL Table functions to give me what I need:

1. Subsystem library name
2. Subsystem name
3. Time started

The first Table function I will use is ACTIVE_JOB_INFO as that can tell me if the subsystem is active or not.

The second is JOB_LOG_INFO, as I need to get the first entry from the job log.

The SQL statement I would use is:

01 SELECT A.SUBSYSTEM_LIBRARY_NAME AS "Library", 02 A.SUBSYSTEM AS "Subsystem", 03 B.MESSAGE_TIMESTAMP AS "Start time" 04 FROM TABLE(QSYS2.ACTIVE_JOB_INFO( 05 SUBSYSTEM_LIST_FILTER => 'QPGMR', 06 JOB_NAME_FILTER => '*SBS')) A, 07 LATERAL 08 (SELECT MESSAGE_TIMESTAMP 09 FROM TABLE(QSYS2.JOBLOG_INFO(A.JOB_NAME)) 10 WHERE ORDINAL_POSITION = 1) B ;

Lines 1 – 3: These are the columns I desire, and I have given them meaningful headings.

Lines 4 - 6: Here we have the ACTIVE_JOB_INFO Table function, and the two parameters I am passing to it:

1. SUBSYSTEM_LIST_FILTER:  Name of the subsystem, in this example it is 'QPGMR'
2. JOB_NAME_FILTER:  The type of job I am interested in, here it is the subsystem itself

Line 7: Using the LATERAL I can include the results from a subselect using a column from the first part.

Lines 8 – 10: This is the subselect. I want the job log message timestamp returned. I using the JOBLOG_INFO Table function passing the job name from the ACTIVE_JOB_INFO. I am only interested in the first entry in the joblog, therefore, to select that I must use the ORDINAL_POSITION column.

The results are the same as those from example 1.

Library Subsystem Start time ------- --------- -------------------------- QSYS QPGMR 2021-02-22 09:24:53.752041

If no result is returned the subsystem is not active.

 

This article was written for IBM i 7.4, and should work for some earlier releases too.