What is the meaning of MAXRBLK value in DSNZPARM display?

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Issue/Introduction

In Thread Terminator DSNZPARM Display, MAXRBLK value is displayed as 12500 but in DSNZPARM source was specified as 400000.
 
DESCRIPTION                                      VALUE      KEYWORD
------------------------------------------------ ---------- -------
Max 32K RID blocks allowed.                      12500      MAXRBLK

Environment

Release:
Component: PTT

Resolution

The MAXRBLK DSNZPARM actually specifies the amount of storage in Kilobytes that is needed for the RID pool. When DB2 DSN6SPRM macro is assembled, the value of the MAXRBLK DSNZPARM itself is not stored. Instead, the value of the MAXRBLK DSNZPARM is divided by 32, giving the max number of 32K RID blocks. The proof is in the output for the DSNTIZA step in the DSNTIJUZ job, where you'll find this:
 
0000E8 000030D4 ... 115+SPRMRMAX DC AL4(400000/(8*4)) ... # OF RIDPOOL RIDBLKS @K0330

So Thread Termination/Dynamic DSNZPARM (PTT) is actually displaying the correct "Max 32K RID blocks allowed" value of 12500, which is derived from the MAXRBLK value of 400000. Note that 400000/(8*4) = 12500.