Thanks for your help, and all the help you provide to people on this list. Your replies are always quick, professional, and helpful.
A big part of what makes Tomcat so great is the assistance that can be found on this list! 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: Mark Thomas <ma...@apache.org> Sent: Friday, July 9, 2021 1:31 PM To: users@tomcat.apache.org Subject: Re: [Possible Spam] Re: HTTP/2 Memory Leak 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 > > ------------------------------------------- > Confidentiality Notice: OCIESERVICE > ------------------------------------------- > The contents of this e-mail message and any attachments are intended solely > for the addressee(s) named in this message. This communication is intended to > be and to remain confidential. If you are not the intended recipient of this > message, or if this message has been addressed to you in error, please > immediately alert the sender by reply e-mail and then delete this message and > its attachments. Do not deliver, distribute, copy, disclose the contents or > take any action in reliance upon the information contained in the > communication or any attachments. > > > -----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. >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org >> For additional commands, e-mail: users-h...@tomcat.apache.org >> > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
