Re: Memory control
Re: Memory control
- Subject: Re: Memory control
- From: Philippe Rabier <email@hidden>
- Date: Mon, 14 Mar 2011 13:49:31 +0100
Don't forget you can also schedule your instances with WOMonitor.
However, I know some "big" apps that are running several weeks without restart. So it's not a fatality…
There is also JProfiler that is good tool (but not free).
And there is an interesting WOWODC'08 video about Shark (I hope Shark is still usable with java applications).
http://www.wocommunity.org/webobjects_screencasts.html
Philippe
On 14 mars 2011, at 11:52, Q wrote:
> Try using jvisualvm or a similar tool to get a heap dump of the JVM after it has been running for a while so you can see where the memory is actually being used.
>
> On 14/03/2011, at 6:36 PM, Gennady Kushnir wrote:
>
>> Hello again everybody.
>> I still hope somebody would answer.
>> I'va made GC logging with -XX:+PrintGCDetails and I see some
>> interesting things happening.
>> It seems like some uncollectable garbage is being accumulated in memory.
>> Within the first hour heap usage goes up 35M and then within next 6
>> hours falls back to that number after rare fullGC acts.
>> After 8 hours that lower limit goes up to 40M, after 20 hours - to 45M
>> and fullGC acts happen significantly more often.
>> After 30 hours heap usage would not fall lower 50M and after 35 hours
>> almost every GC is fullGC. Since 60 hour lowest heap usage is 55M.
>> Finally at about 95 hours I get OutOfMemory error as the heap is
>> limited by default to 64M.
>>
>> So my question is - what should I do now?
>> Is it expected behavior for large WO application?
>> Should I simply rise max heap limit to find memory amount that would be enough?
>> Should I schedule WOMonitor to restart the App every night?
>> Or such behavior should be considered as my error somewhere in code?
>> So where should I look for memory leaks?
>>
>> 2011/3/3 Gennady Kushnir <email@hidden>:
>>> Hello All!
>>> I would raise this topic again. Thanks for all tips you have me.
>>> Jprofiler is too commercial for me unfortunately. And VisualVM failed
>>> to run on my deployment system (Xserve G4).
>>> In fact even when run on my dev system, I could not actually figure
>>> out how it could help me :(
>>> I feel sad about I loosely know many aspects in Java technology. Could
>>> you give me some links where to read about such things as "Eden",
>>> "young generation" and "survivors" - I did not get these terms.
>>>
>>> And about those ec's that don't get garbage collected. After
>>> eliminating all references to EO's outside components I still could
>>> not get rid of that issue.
>>> When debugging I've finally noticed inside a WOSession object an
>>> NSMutableDictionary called _contextRecords, which holds hard
>>> referenced on ALL previously used components. Even though I have
>>> reduced pageCacheSize to 5 in an Application constructor.
>>> And those components hold references to those ec's so they can't get
>>> garbage collected...
>>> Sad...
>>>
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