Limits and Statistics

Discussion created by ca.portal.admin on Jun 19, 2008
Hello Listers, At our site we are looking at ways to reduce the CPU usage=
of the IDMS CV's. I remember seeing some statistics stating that having =
statistics collection on added approximately 8 - 10% CPU overhead. Also, =
turning on LIMITS increased the CPU usage roughly 7%. I have found some i=
nternal documentation that states this, but I cannot find any 'official' =
CA documentation that does. Does anyone else on the list remember seeing =
similar statements about the CPU overhead of LIMITS & STATS? The reason f=
or the question is that I ran some tests on one of our CV's. Using a test=
ing tool we ran almost 70,000 tasks thru the CV with LIMITS enabled and S=
TATISTICS collection on. We then shutdown the CV and recorded the # of ta=
sks, CPU used, etc. Next we changed the SYSGEN to set LIMITS disabled and=
STATISTICS off. We also changed the #PMOPT macro to stop writing SMF dat=
a. We reran the exact same set of scripts. The results showed only a 2% r=
eduction in CPU usage. Does this figure surprise anyone else? Any ideas w=
hat I could be missing to only see this small reduction? Thanks for any h=
elp you can give. Dan Hall GE Capital Solutions Database Administrator T =
513.217.5060 E Middletown, O=
H 45042 General Electric Capital Corporation
IDMS 3rd-party providers forum


Re: Limits and Statistics

If you're using ADSO, you can reduce CPU by removing retrieval locks where they're not needed. If you have dialogs that are used allot during the day, are mostly retrieval and do only a small amount of updating, you can put the updating functions in a mapless dialog, do a 'LINK NOSAVE' from the retrieval dialog to the update dialog, have the update dialog re-establish currency and turn retrieval locks off in the retrieval only dialogs. If a dialog is retrieval only and does not pass currencies to an update dialog, the retrieval locks should be turned off. This could save allot of CPU and also reduce deadlocking depending on how the dialogs are coded and the number of transactions they process.