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| Robmar_VE |
 Posted: Wed Jun 14, 2017 10:31 am Post subject: Help! High consumption in EG`S swap memory. |
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Newbie
Joined: 14 Jun 2017
Posts: 8
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Hello everyone,
I have the following issue, I have a solution with more than 40 EG`S, all are presenting high swap memory consumption over 80%.
Checking should change or activate the garbage collector, however I do not know the parameter to change.
I hope you can help me, WebSphere MQ 7.5.0.5 product version under Linux.
Sorry my bad english.
Thank you.- |
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| Vitor |
| Posted: Wed Jun 14, 2017 10:53 am Post subject: Re: Help! High consumption in EG`S swap memory. |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| Robmar_VE wrote: |
| Checking should change or activate the garbage collector, however I do not know the parameter to change. |
Has this just started happening? How do you know it's not a badly written application failing to release JVM memory?
The GC for the EG JVM is active by default. I'm not convinced you can either disable it, enable it, enable it more or configure how often it runs.
I'm also told by people who know Java better than I do (which is almost everyone that knows Java) that changing the GC settings where you can (like on WAS) is a great way to kill performance.
How much memory is 80% of your swap? Maybe you just need more swap for the load you're running.
| Robmar_VE wrote: |
| Sorry my bad English |
I work with Americans. You're fine.
_________________
Honesty is the best policy.
Insanity is the best defence. |
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| Robmar_VE |
| Posted: Wed Jun 14, 2017 11:10 am Post subject: |
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Newbie
Joined: 14 Jun 2017
Posts: 8
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Hi @Victor,
Yes, I have little experience in Message Broker administration.
I discard some application since the code has been thoroughly revised and is correct, currently the environment does not have much operational load.
Modifying the following EG`S parameter jvmMinHeapSize OR jvmMaxHeapSize controls the frequency with which the GC runs.
RAM memory 11 gb and SWAP 8 gb, currently the total RAM memory and 80% or 90% of the swap memory are consumed.
Thanks for your help. |
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| Vitor |
| Posted: Wed Jun 14, 2017 12:19 pm Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| Robmar_VE wrote: |
| I discard some application since the code has been thoroughly revised and is correct |
If I had $5 for every time code that was "thoroughly revised and is correct", and also had been running for some time went crackers, I'd have retired.
| Robmar_VE wrote: |
| Modifying the following EG`S parameter jvmMinHeapSize OR jvmMaxHeapSize controls the frequency with which the GC runs. |
Point taken. I meant that you couldn't directly reference the GC, only influence it with these settings.
So what do you have them set to?
| Robmar_VE wrote: |
| RAM memory 11 gb and SWAP 8 gb, currently the total RAM memory and 80% or 90% of the swap memory are consumed. |
So just to be clear, are you talking about JVM memory or system swap being used?
You've also mentioned MQ 7.5.0.5 and Linux, but not what distro/version. Also what version of IIB please?
_________________
Honesty is the best policy.
Insanity is the best defence. |
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| nelson |
| Posted: Wed Jun 14, 2017 2:28 pm Post subject: Re: Help! High consumption in EG`S swap memory. |
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Partisan
Joined: 02 Oct 2012
Posts: 313
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| Vitor wrote: |
| Has this just started happening? |
Key question.... please answer the same... |
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| fjb_saper |
| Posted: Wed Jun 14, 2017 7:56 pm Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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| Robmar_VE wrote: |
Hi @Victor,
Yes, I have little experience in Message Broker administration.
I discard some application since the code has been thoroughly revised and is correct, currently the environment does not have much operational load.
Modifying the following EG`S parameter jvmMinHeapSize OR jvmMaxHeapSize controls the frequency with which the GC runs.
RAM memory 11 gb and SWAP 8 gb, currently the total RAM memory and 80% or 90% of the swap memory are consumed.
Thanks for your help. |
I am not surprised! If you are running 40 egs across Y brokers, I'd say if you have only 11GB as RAM for the box you are grossly undersized.
Upgrade that to 32GB of memory for the box and see how you fare, and if you still use swap file space.
Also know that in order to release memory you'd have to run mqsireload. The memory is probably not held in Java but at the C level.
Typically the broker does not release memory because it expects to reuse it in the next instant....
So if you are running some batch processes that are memory intensive you may want to reload the eg(s) once your batches are done to free the memory...
Have fun 
_________________
MQ & Broker admin |
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| Robmar_VE |
| Posted: Thu Jun 15, 2017 5:19 am Post subject: |
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Newbie
Joined: 14 Jun 2017
Posts: 8
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Yes, this is being presented now ... The strange thing is that no changes were made.
The affected memory is the system's own swap, not the JVM. But what affects the swap memory are the DataFlowEngine that execute the different EG`S.
Name: WebSphere QM
Version: 7.5.0
O / S: Linux 2.6 x86_64
IIB Version: 9.0.0
Increasing the memory would not solve the problem, in a test made increase the memory to 16 gb and occurred exactly the same, I take more time to occupy the memory but still occupy.
I need to configure the GC or some memory limiter more appropriately.
Thank you |
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| mqjeff |
| Posted: Thu Jun 15, 2017 6:33 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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First confirm which EGs are using up the memory.
Then bang on the developers of the flows in those EGs to review their code.
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