Cris,
> -----Original Message----- > From: Berneburg, Cris J. - US <cberneb...@caci.com.INVALID> > Sent: Thursday, May 27, 2021 2:24 PM > To: users@tomcat.apache.org > Subject: [OT] web app big memory usage? > > Hi Folks :-) > > One of our web apps is using a "lot" of memory, specifically a big user query. > We'd like to find out why. > > The Tomcat Web Application Manager Find leaks button said that "No web > applications appear to have triggered a memory leak on stop, reload or > undeploy." > > Tomcat Manager Server Status shows that 1.7GB (82%) of G1 Old Gen space > is being used that has not been recycled yet. > > I grabbed a heap dump and used Eclipse Memory Analyzer, and it shows that > only 94MB of memory is being used when G1 Old Gen space used 1.8GB. > MAT seems to be looking only at the active objects, not the discarded ones. > IOW, we're looking at what the app is doing ATM, not what it already did. > > I want to explore the 1.7GB garbage pile to see what's being thrown away, > not what things are still being used, to determine wastefulness. > > 1. Is there a way to analyze uncollected garbage? > > 2. Is that a reasonable way to identify potential memory usage problems? > > Some technical specifics: > * TC 8.5.63 > * Java 1.8.0_291 > * AWS EC2 instance. > * Windows Server 2016. > * Instance started as Windows Service. > * There are other TC instances on the same server. > * Each TC instance has multiple apps. > > Thanks for reading this far. :-) > > -- > Cris Berneburg > CACI Senior Software Engineer > > > ________________________________ > > This electronic message contains information from CACI International Inc or > subsidiary companies, which may be company sensitive, proprietary, > privileged or otherwise protected from disclosure. The information is > intended to be used solely by the recipient(s) named above. If you are not > an intended recipient, be aware that any review, disclosure, copying, > distribution or use of this transmission or its contents is prohibited. If you > have received this transmission in error, please notify the sender > immediately. > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org MAT has an option to "Keep unreachable options." It's under preferences. It sounds like you don't have an actual leak, just high allocation/GC. My favorite tool for this is to use the Java Flight Recorder and analyze it with Java Mission Control. John --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
