Thanks Rémy! That helped a lot. It would be nice to have that in the migration guide.
ср, 17 июл. 2019 г. в 17:02, Rémy Maucherat <r...@apache.org>: > On Wed, Jul 17, 2019 at 3:19 PM Mozgo Andrei <andrei.mo...@gmail.com> > wrote: > > > Hi all. > > > > Working on Update Tomcat 8.0.30 to Tomcat 9.0.14 I faced with a memory > > leak issue. The application failed after some hours with the next > > exception: > > > > > > > > *Caused by: java.lang.OutOfMemoryError: GC overhead limit exceeded* > > > > > > The memory was completely consumed and the garbage collector was > > struggling all the time trying to free it: > > [image: 1.png] > > > > > > Heap Dump contained 120 instances of > > org.apache.catalina.connector.Response each consumed 10Mb of memory: > > [image: image.png] > > > > I found out that the next Tomcat version 9.0.16 contains a fix for a > bunch > > of memory leak issues. Upgrade to 9.0.16 just doubled hour application > > worked then it fails with the same issue. However, it could just be a > > temporary load decrease. > > > > > > > > I tried to use Tomcat 8.5.16 that works fine with another module. Another > > module heap dump didn't contain any instances of > > org.apache.catalina.connector.Response even after more than 116 hours. > > However, Tomcat 8.5.16 didn’t solve the problem. The application failed > > with the same error and heap dump looked the same. > > > > > > Then I looked into the heap dump of the application working on Tomcat > > 8.0.30. It contained instances of org.apache.catalina.connector.Response > as > > well. But their size was much smaller: > > > > > > [image: image.png] > > > > It looks like there is a memory leak issue with > > org.apache.catalina.connector.Response in all Tomcat versions (8, 8.5, 9) > > with the only difference in the size of OutputBuffer which is a part of > > Response: > > [image: image.png] > > Here are GC roots of Response instance: > > [image: image.png] > > > > Could you please give a piece of advice on how to manage with this? > > > > First, having Response and OutputBuffer instances is normal. The > OutputBuffer implementation was changed from using our own Byte/CharChunk > impl to using Byte/CharBuffer. This is "ok" but has some side effects on > memory use. In particular if response.setBufferSize is used. If it is, > while previously it set an upper limit to which the buffer would gradually > grow as needed, now it simply has to allocate the whole buffer. You might > want to look into that. > Also, the previous code used to discard the allocated char array, while now > it is not possible. > > So now you have to be careful with use of setBufferSize (which is ok since > using it is a very bad idea, the default is fine as it is and will perform > well). > > Rémy > > > > > > Thanks, > > Andrei Mozgo > > >
