I enabled MEMDSENQMGT with zOS 1.12. Also started to use it in our
sysres build program;
IEFDDSRV MODIFY,TYPE=FEATURE,DSENQMGMT=MEMORY USE MEMORY-BASED
* DATA SET ENQ
* MANAGEMENT FOR
* DYNAMICALLY
* ALLOCATED DATA
* SETS
Barbara Nitz <mailto:[email protected]>
October 30, 2017 at 2:45 AM
We have been running with USEZOSV1R9RULES( NO) for the past 1.5 years,
ever since I set it when I joined the company. We did not have any
issues, and we run mostly DB2 in addition to homegrown stuff.
If you go back in the archives you'll find the discussions about that
parm in detail. The 'side effect' (IIRC) of setting the parm to NO and
using the better performing behavior is that VSM now doesn't clear the
storage it hands out to binary zeros anymore (only for the cases
explicitly stated in the documentation). So if you have a home-grown
application that has relied on getting hex zeros despite not having
followed the docs, that may lead to some rude awakening because there
might be some residual storage left that wasn't cleared. These days I
would guess it is only home-grown applications that would suffer any
problems.
Back when the parm first came out, I used the (undocumented except
partially on ibmmain) DIAGxx traps that fill any storage (and
registers and the PSA) with hex FFFFFFFF to attempt to test our
applications. I found a number of OEM products that abended with
abend0c4/0C6/0C1, but one of the home-grown Assembler exits was also
falling all over itself because it wasn't coded correctly.
I am sad to say that MEMDSENQMGMT has escaped my notice. I'll turn
that on in the sandplex and see how it goes.
Barbara
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [email protected] with the message: INFO IBM-MAIN
Please be alert for any emails that may ask you for login information
or directs you to login via a link. If you believe this message is a
phish or aren't sure whether this message is trustworthy, please send
the original message as an attachment to '[email protected]'.
--
Mark Jacobs
Time Customer Service
Global Technology Services
The standard you walk past is the standard you accept.
Lt. Gen. David Morrison
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [email protected] with the message: INFO IBM-MAIN
