Performance to use $ACCESS TYPE=EXECUTE

Products

• PDSMAN

Issue/Introduction

Customer found that TYPE=EXECUTE is very useful and will implement TYPE=EXECUTE. To use TYPE=EXECUTE, they asked some questions.

1 Some additional overhead on TYPE=EXECUTE. Customer asked how many CPUs would be increased to specify TYPE=EXECUTED on $ACCESS statement. 

2 Customer has a large load library dataset. All batch jobs in the customer’s system will access the dataset.

Environment

Release:
Component: PDSM

Resolution

1) The additional overhead is minimal, probably not even measurable. When it is a load module or program object, it is simply a matter of checking the DCB used – LINKLIST or JOBLIB/STEPLIB for example. But when it is a Clist, REXX exec, or JESn procedure we scan thru a table of program names to make the determination of TYPE=EXECUTE. The scan thru the table is the addition overhead (and is minimal as I said).

2) They may see more SMF records being recorded (assuming they don’t already have the 2nd rule). I don’t think they would even notice a difference in CPU usage. There would be no other implications (no additional I/O to the directory for example).