Thread Terminator ZPARM display shows MGEXTSZ as YES but the value is really NO

Products

• Thread Terminator for DB2 for z/OS

Issue/Introduction

The Thread Terminator for Db2 for z/OS (PTT) ZPARM display shows MGEXTSZ as YES but the zparm value is really NO: 

From the zparm source the parm has been set to NO:
MGEXTSZ=NO,                                             X

 

From the Thread Terminator DSNZPARM display it shows as YES:
DB2 managed SQTY for DB2-managed data sets .     YES        MGEXTSZ
   

This appears to occur on ALL subsystems. 

Environment

Release : 20.0
Component : Thread Terminator for Db2 for z/OS 

Cause

IBM APAR PH28280: DB2 12 ZPARM SIMPLIFICATION CONTINUED:REMOVE CACHEPAC, CACHERAC, IRLMAUT, IRLMSWT,
EDPROP, CHGDC, PCLOSEN, AND MGEXTSZ.

Resolution

In Db2 12 the MGEXTSZ parameter still exists, but it's set to "Yes" and not editable. This behavior was introduced in the APAR PH28280.

The Db2 code sets the MGEXTSZ parameter to “Yes”, ignores any value set in the input parameter member, and displays this message:
“MGEXTSZ CAN NO LONGER BE SPECIFIED”.

Setting the “MGEXTSZ=NO,    X” in the zparm source will have no effect on the MGEXTSZ parameter value.
In this case the Thread Terminator VZ - View DSNZPARM Data option will display the MGEXTSZ parameter as “Yes”.      

Thread Terminator’s "U - Update DB2 Parameters" option still allows a user to update the MGEXTSZ parameter
and change it to “No”, but the change doesn’t affect DB2.  Internally DB2 still views the MGEXTSZ parameter as “Yes”.
 In this case the “VZ - View DSNZPARM Data” option will display the MGEXTSZ parameter as “No”, but it’s still a “Yes” internally in Db2.

Additional Information

IBM APAR PH2828