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I have a Weblogic server which has Memory Utilization (MU), taken from DynaTrace APM, as shown in below table.

My understanding of memory utilization is that it is amount of memory used by program. Now it certainly cannot be maximum and minimum because it will not truly represent utilized (right?) so I am going to average out below % and I am getting 52%.

So does it mean that memory footprint is 52%?

Second question: These statistics are from a APM. Now I also I have maximum memory and memory used. If I do simple calculation to calculate memory utilization (MU) manually by (memory-utilized/maximum-memory) then I do not get exact same figure as given by APM for same time in MU chart.

  • Does it mean that I cannot calculate memory footprint simply as (memory-utilized/maximum-memory)?

  • APM does more calculation for getting true memory foot print? So how can I calculate memory foot print on my own?

    **Date**            **MU (%)**
2016-01-26T15:15:00 42.47219781
2016-01-26T15:30:00 46.03047265
2016-01-26T15:45:00 46.54384698
2016-01-26T16:00:00 47.25852017
2016-01-26T16:15:00 48.60865614
2016-01-26T16:30:00 50.23378059
2016-01-26T16:45:00 51.82248162
2016-01-26T17:00:00 51.95340814
2016-01-26T17:15:00 52.77441474
2016-01-26T17:30:00 52.83012288
2016-01-26T17:45:00 52.85740628
2016-01-26T18:00:00 54.01675551
2016-01-26T18:15:00 54.40046963
2016-01-26T18:30:00 54.79707947
2016-01-26T18:45:00 54.9685574
2016-01-26T19:00:00 56.83530307
2016-01-26T19:15:00 55.7976905
2016-01-26T19:30:00 57.44057855
2016-01-26T19:45:00 57.22555271
2016-01-26T20:00:00 57.19549255
2016-01-26T20:15:00 56.95526801
2016-01-26T20:30:00 57.41918165
2016-01-26T20:45:00 57.93780653
2016-01-26T21:00:00 57.42303196
pjj
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  • In a system with virtual memory, there are many ways to try and measure memory utilization. What operating system is this, and what program is it that produces these figures? – Dolda2000 Jan 29 '16 at 15:28
  • @Dolda2000 Is a Linux box and stats are for JVM. It is a Weblogic server. – pjj Jan 29 '16 at 15:29
  • Still, where do these figures come from? What program is it that produces them? There are many ways to calculate memory utilization figures for Java as well. – Dolda2000 Jan 29 '16 at 15:30
  • It is produced by DynaTrace APM. – pjj Jan 29 '16 at 15:31
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    I myself do not know of DynaTrace APM, but I would argue that this whole question pertains to it, specifically, in that these figures are peculiar to the way DynaTrace APM calculates the figures. Unless there's someone around who knows how it works in detail, I'd recommend checking its documentation for your answer. Also, I'd recommend editing the question to reflect that the figures come from DynaTrace APM, since that's the only context in which the question can be meaningfully answered. – Dolda2000 Jan 29 '16 at 15:34
  • I have edited by question to include DynaTrace APM. How does it matter whether it come from which APM, lets say it comes from other APM, now if these are the figures then can I average out the stats and get my foot print. And how about my second question, any idea please? – pjj Jan 29 '16 at 15:40
  • Well, the thing is that there is no single definition of "memory utilization" that can be spoken of for Java programs in general. The JVM and surrounding environment provides many different raw variables that can be used to put together such a figure, and this particular definition is, therefore, specific to DynaTrace. Without knowing how DynaTrace defines it, there's no way to answer your question. – Dolda2000 Jan 29 '16 at 15:43
  • I don't know if DynaTrace is a popular program, but in the case there aren't people around here who are knowledgeable about it, you may want to measure your program's memory utilization with standard tools such as `jstat`, which comes with the JVM and therefore may be available to a wider audience. Just trying a different tool may indeed reveal more subtleties to yourself as well. – Dolda2000 Jan 29 '16 at 15:46
  • Lets say I do not have any APM, and I calculate used memory (using Java memory beans) in some regular interval and then divide by max memory. So, that I have memory utilization. First question - would it be memory utilization? Second question - lets say I am good with what DynaTrace provides, now can I average out to get memory footprint? If not then how do I calculate memory footprint? – pjj Jan 29 '16 at 15:48
  • "*Would it be memory utilization?*", you ask. There are many things that could be spoken of as "memory utilization" and "memory footprint". There's no single, general definition of these terms -- rather the opposite, memory usage is a rather complex subject once you scratch the surface. If you aren't knowledgeable about it enough to formulate the precise definition you want, I would suggest you specify with some precision what it is that you want to measure and why, so that someone can perhaps figure out some definition(s) that seems suitable to your purposes. – Dolda2000 Jan 29 '16 at 15:54
  • Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/102014/discussion-between-pjj-and-dolda2000). – pjj Jan 29 '16 at 16:36

1 Answers1

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If you have tool specific questions on Dynatrace APM I suggest you post them on our APM Open Q&A Discussion forum:

I also have a YouTube Tutorial on Memory Analysis with Dynatrace in case thats of interest.

Andreas Grabner
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