On 09/07/2021 18:23, Mark A. Claassen wrote:
Thank you so much! This is good to know.
We may not change anything then (until that server gets upgraded). However,
would switching back to HTTP 1.1 reduce the memory footprint in the mean time?
Yes.
The issue is the HTTP/2 priority tree. Essentially, Tomcat has to keep
some information around about the previous few hundred requests on every
HTTP/2 connection. Until .37/.39 Tomcat just kept objects used for the
request/response. As of .37/.39 Tomcat replaces these with a much
lighter object once the request is completed.
Would the connection be cleaned up when the browser goes away?
Should be.
Mark
Mark Claassen
Senior Software Engineer
Donnell Systems, Inc.
130 South Main Street
Leighton Plaza Suite 375
South Bend, IN 46601
E-mail: mailto:mclaas...@ocie.net
Voice: (574)232-3784
Fax: (574)232-4014
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-----Original Message-----
From: Mark Thomas <ma...@apache.org>
Sent: Friday, July 9, 2021 12:59 PM
To: users@tomcat.apache.org
Subject: Re: [Possible Spam] Re: HTTP/2 Memory Leak
Importance: Low
On 09/07/2021 16:21, Mark A. Claassen wrote:
Thanks. I have done more heap analysis and think I have it tracked closer to
the source.
--
I started looking at the heap a different way. The random values I looked at
before (of the 80,000) may not have be as representative as I thought.
Examining the retained sizes in the heap, I am finding:
I have two instances of AbstractProtocol$ConnectionHandler.
One of these AbstractProtocol$ConnectionHandler instances has a ConcurrentHashMap called
"connections"
This map as 32 elements in its "table". Most of these are null. Some of the
ones that are not, are huge.
The entirety of the map retains 112MG.
Two of these ConcurrentHashMap$Node elements take up around 50MG a piece.
Looking at the "val" variable of a node, there is an
UpgradeProcessorInternal Inside this is a variable called
internalHttpUpgradeHandler (of type Http2UpgradeHandler) The one of these I am
looking at now retains 16MG of memory.
(Oddly, once I get this far, the retained sizes of its internal
objects don't really add up.)
Any ideas on how to work around this? Or if this is already fixed in a later
version of Tomcat?
That isn't a leak. That is high memory usage. The objects will be GC'd once the
HTTP/2 connection closes.
The changes in 9.0.37 / 9.0.39 should reduce the memory footprint considerably.
Mark
Thanks,
Mark Claassen
Senior Software Engineer
Donnell Systems, Inc.
130 South Main Street
Leighton Plaza Suite 375
South Bend, IN 46601
E-mail: mailto:mclaas...@ocie.net
Voice: (574)232-3784
Fax: (574)232-4014
Disclaimer:
The opinions provided herein do not necessarily state or reflect those
of Donnell Systems, Inc.(DSI). DSI makes no warranty for and assumes
no legal liability or responsibility for the posting.
-----Original Message-----
From: Rob Sargent <rsarg...@xmission.com>
Sent: Thursday, July 8, 2021 6:50 PM
To: users@tomcat.apache.org
Subject: Re: [Possible Spam] Re: HTTP/2 Memory Leak
Importance: Low
On 7/8/21 3:17 PM, Mark A. Claassen wrote:
Ok. That didn’t seem to work. I will investigate further and try to find a
way to send that information.
It is not that busy a server, but the memory use increases very quickly. Doing
a class_histogram shows MessageBytes growing by the thousands every 30 minutes.
(We have a temporary monitor script in place that does a GC and then
prints a class_histogram every half hour to help us pinpoint what is
happening.)
Thanks,
Mark
Perhaps you've done this already, but
grep -R 'static HashMap' src
might locate some potential culprits.
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