Can QGPL Library Safely Be Placed In QSYSLIBL?

The general question regards whether or not it is safe to place QGPL library in the system library list, thus in QSYSLIBL, as opposed to having it remain in the user library list, thus QUSRLIBL. There is no system restriction or fundamental reason why that should not be done. One needs to be careful to not accidentally place the library name in both of the library lists, because that can cause major difficulties.


There is a possibility that some particular application has some dependency that requires that QGPL be in the user library list but hopefully there will be few of those. One should keep in mind that if a particular user uses commands and programs from his own current library for which there are similarly named objects in QGPL, then if the QGPL library is changed from the user library list to the system library list, situations may occur causing the wrong version of these objects to be used. If the object names are library qualified, this problem is not a possibility; whereas if the library qualification is merely *LIBL, this problem could occur.

Listing Last Used Date / Creation Date for all Objects in a Library

Dump all objects in selected library to an outfile:

DSPOBJD OBJ(TESTLIBRARY/*ALL) OBJTYPE(*ALL) OUTPUT(*OUTFILE) OUTFILE(QGPL/OBJDOUT)
Start SQL so we can select the necessary fields in the outfile:
STRSQL
Paste the following:
SELECT ODOBNM, ODLBNM, ODOBTP, ODUDAT, ODCDAT FROM qgpl/OBJDOUT
ORDER BY ODUDAT desc
This will create a display with objects creation date and last used date. You can also print to an outfile by using F13 on the Enter SQL Statements screen and changing the session attributes to print.

What Controls the Creation Date on QTEMP Libraries

QTEMP libraries are not reused across IPLs. New QTEMP libraries are created on each IPL as they are needed. Work Management code calls Librarian code to create a QTEMP library when the job structure is created. After a job ends, the QTEMP library associated with the job is now available for use by another job.
The creation date shown on the DSPOBJD command should be the actual creation date of when the library was created. Because the QTEMP library could be reused, the date/time could be very different from the date/time of when the job started. Therefore, the QTEMP creation time is the time that a previously created job structure is first used after an IPL or when a new job structure is created.

Important Libraries Information

Following describes some of the system libraries and their purpose. Those libraries are QDCT, QDOC, QDSNX, QFNTCPL, QGDDM, QGPLTEMP, QGYY, QHTTP, QIWSPS, QPDP, QPFRDATA, QPWXCGY, QPWXCPC, QQALIB, QRUMBA, QRUMBAD, QRUMBA2, QSRV, QUPGRADE, QUSRINFSKR, QUSRTEMP, and QWSG.