Re: Memory control
Re: Memory control
- Subject: Re: Memory control
- From: Chuck Hill <email@hidden>
- Date: Thu, 17 Mar 2011 07:59:35 -0700
On Mar 17, 2011, at 2:08 AM, Gennady Kushnir wrote:
>> Hi,
>
>>> Finally at about 95 hours I get OutOfMemory error as the heap is
>>> limited by default to 64M.
>>
>> 64M seems small to me for a Java app.
> I did not do any memory regulations myself. It is just default on my
> absolutely standard deployment system for WO (Xserve G4 , 2GB, MacOS X
> 10.5, Java 1.5.0_24)
>
> I found this 64M doing
> ps ax | grep "java"
>
> It lists all WO apps like this:
> /usr/bin/java -XX:NewSize=2m -Xmx64m -Xms32m -DWORootDirectory=/System ...
If you look at the entire line, you will often see these set multiple times with different values. The last one is what is used.
Chuck
>
> So as I understand "-Xmx64m" - that is maximum heap size.
> Actual memory usage for whole JVM is about 300M.
>
>>> So my question is - what should I do now?
>>> Is it expected behavior for large WO application?
>>
>> Using 64M+ of memory is, the increasing heap size is not.
> What are other means to increase memory used?
>
>>> Or such behavior should be considered as my error somewhere in code?
>>> So where should I look for memory leaks?
>>
>> You mentioned before exceptions, that is where I would start. Also check that your session sleep(), awake(), and terminate() can never throw an exception. If you are getting deadlocked sessions, then the session, page cache, and related EOs will never get garbage collected.
>
> Most exceptions I get now are cased by "java.lang.OutOfMemoryError:
> Java heap space"
> So that is what I am trying to get rid of.
> I get any other exceptions not more often than once a month whereas
> OutOfMemoryError comes nearly every 5th day =(
>
>> Also check that your session sleep(), awake(), and terminate() can never throw an exception.
> Would I see such exceptions in log if they happen? I did not see any yet.
>
>> Beyond that, I would try a heap analyzer to see what the objects are that do not get collected.
> What is "heap analyzer" ? And where can I get it?
>
> Gennady
--
Chuck Hill Senior Consultant / VP Development
Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems.
http://www.global-village.net/products/practical_webobjects
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