2015-03-21 12:37 GMT+02:00 Антон Мацюк denixx.bay...@gmail.com:
2015-03-21 2:06 GMT+02:00 Eric Robinson eric.robin...@psmnv.com:
Set this options to JVM, and it will make heapdumps automatically.
Will these heap dumps be the same size as the current tomcat memory
utilization?
Yeap, and OOM
//
One correction, option -XX:-HeapDumpOnOutOfMemoryError disables heapdumps on
OOM, you should use -XX:+HeapDumpOnOutOfMemoryError - with plus sign, to enable
it.
//
Thanks for the follow-up.
--Eric
2015-03-21 2:06 GMT+02:00 Eric Robinson eric.robin...@psmnv.com:
I think if you have vendor-locked app in vendor-locked environment (am I
right?)
Yes indeed.
So, worth a try, at least.
Set this options to JVM, and it will make heapdumps automatically.
Will these heap dumps be the same size
//
I think if you have vendor-locked app in vendor-locked environment (am I
right?)
//
Yes indeed.
//
As I said above, there is an options for JVM:
-XX:-HeapDumpOnOutOfMemoryError - it will make heapdump on OOM.
-XX:HeapDumpPath=./java_pidpid.hprof - give it an reasonable path to file.
Set
2015-03-20 22:29 GMT+02:00 Eric Robinson eric.robin...@psmnv.com:
Very good information. I much prefer finding the actual root causes of
things rather than just bumping the memory, but I'm not sure how much that
would help because the best I can do is report the issue to the vendor.
2015-03-20 1:15 GMT+02:00 Eric Robinson eric.robin...@psmnv.com:
Heap dumps?
What we do is called a thread dump, as far as I know. We use kill -3 on
Linux, which dumps the thread activity. The memory data shows up at the
bottom of that. See:
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Hash: SHA256
Eric,
On 3/19/15 7:15 PM, Eric Robinson wrote:
Christopher Shultz wrote: // Time to upgrade. Tomcat is hideously
out of date (probably because you are using RedHat's Tomcat
package), at least by version number. I'm not sure what RedHat
does
From: Eric Robinson [mailto:eric.robin...@psmnv.com]
Subject: RE: Java Heap Space / Thread Dump Numbers
If you have the option, you might want to run a 32-bit JVM; it will
probably run leaner
and faster than a 64-bit JVM will.
What do you mean my faster and leaner?
Mostly leaner
//
You can look for biggest objects in heap (using MAT, Leak Suspects report,
Dominators Tree report).
This way you can try to find what was the exact reason of OOM instead of just
thinking eh, I need to give instances more memory.
MAT does things good. I've already found using MAT+JVVM the
//
Mostly leaner - a 32-bit JVM uses 32-bit pointers, so object references consume
less heap and stack space. Whether or not the code runs faster or slower
depends on what you're doing, since the tradeoff is fewer registers available
in 32-bit mode, which can lead to more register spills and
//
Yeah, heapdumps.
I've posted above some howtos, have you looked at them?
//
No, I'm not sure how useful I would find them. I think the heap summary is
probably all I need, but I may be wrong. Would the heap dump provide more
actionable intel as far as tuning my memory parameters?
--Eric
//
Recent 64-bit JVMs will automatically use -XX:+UseCompressedOops.
I'm not sure about your version, specifically. If you have the option, you
might want to run a 32-bit JVM; it will probably run leaner and faster than a
64-bit JVM will.
//
Interesting. What do you mean my faster and leaner?
2015-03-20 22:09 GMT+02:00 Eric Robinson eric.robin...@psmnv.com:
I've posted above some howtos, have you looked at them?
No, I'm not sure how useful I would find them. I think the heap summary is
probably all I need, but I may be wrong. Would the heap dump provide more
actionable intel as
From: Eric Robinson [mailto:eric.robin...@psmnv.com]
Subject: RE: Java Heap Space / Thread Dump Numbers
Would the heap dump provide more actionable intel as far as tuning my memory
parameters?
It would provide information about what types of objects are consuming the heap
space. From
Christopher Shultz wrote:
//
Time to upgrade. Tomcat is hideously out of date (probably because you are
using RedHat's Tomcat package), at least by version number. I'm not sure what
RedHat does (if anything) about security fixes, etc. but a vanilla 6.0.18 is
probably vulnerable and has been for
Eric, if you are looking for a reasons and think, what can be done
with OOMs, take a look at this page:
http://www.oracle.com/technetwork/articles/java/vmoptions-jsp-140102.html
There is an options:
-XX:-HeapDumpOnOutOfMemoryError - it will make heapdump on OOM.
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Eric,
On 3/19/15 11:15 AM, Eric Robinson wrote:
Thanks for the feedback. We run various versions of RHEL (5.5 to
6.3) x64. Tomcat is mostly 6.0.18. Java is mostly 6u21 x 64.
Time to upgrade. Tomcat is hideously out of date (probably because you
PSYoungGen total 95808K, used 22323K [0x2aaac377,
0x2aaaca21, 0x2aaaca21)
eden space 82432K, 10% used
[0x2aaac377,0x2aaac402f7f8,0x2aaac87f)
from space 13376K, 99% used
[0x2aaac87f,0x2aaac94fd5a8,0x2aaac950)
to
From: Eric Robinson [mailto:eric.robin...@psmnv.com]
Subject: Java Heap Space / Thread Dump Numbers
PSYoungGen total 95808K, used 22323K [0x2aaac377,
0x2aaaca21, 0x2aaaca21)
eden space 82432K, 10% used
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