VERIFIED SOLUTION i

Resolve TABLSZ parameter with position 25 =Y slowing down process in MailStream Plus

Product affected: MailStream Plus™
Operating System: Linux
 

Issue

The TABLSZ parameter is primarily used when it's required that tables be manually increased in size for MailStream Plus™ (MSP) processing.

But when using TABLSZ with sub keywords STMT or TLBLKS, position 25 of the parameter can be used to control whether a disk file is used to store internal calculation records, or memory is used.
Y means use disk.
N means to use memory.
 
Sub keyword STMT is used for Postage Statement and Statement Summary calculations. The default is N, to use memory.
The default for TLBLKS  is Y, to use disk files. (TLBLKS are Threaded List Blocks, used internally during the presort process.)

This affects other Operating Systems as well, to some degree or other.  But specifically a job was being run on Linux for the first time.  It was found that it was taking about 8 times longer than expected, based on running the same job on a UNIX machine.

All of the extra time was being used by the MSRPFM30 program, which generates Postage Statements and Postage Summaries.
(FYI- MSRPFM10, MSRPFM20, and MSRPFM40 are also Postage Statement/Summary programs.)

Cause

The job had a Y in the TABLSZ STMT parameter position 25, telling MSP to use disk instead of the default internal memory.
When the Y was removed, the job completed in the expected amount of time.

It is not known specifically why using disk on UNIX did not slow the job down, but on Linux it did.  Evidently something about the Linux's hard drive I/O.

Resolution

UPDATED: March 13, 2019
In this case the resolution was to remove the Y from position 25 of the TABLSZ STMT parameter.