[GitHub] [pulsar] lhotari edited a comment on issue #6054: Catastrophic frequent random subscription freezes, especially on high-traffic topics.

[GitBox <gi...@apache.org>]

lhotari edited a comment on issue #6054:
URL: https://github.com/apache/pulsar/issues/6054#issuecomment-841851244


   > I also noticed this warning in the logs after it had been stuck for a while, but I'm not sure if it's related:
   
   @devinbost  Very interesting that there are some Zookeeper related issues happening at the same time (`org.apache.zookeeper.ClientCnxn$SessionTimeoutException: Client session timed out, have not heard from server in 10302ms for session id 0x1028ed903dd038f`) . 
   
   It would be very useful to get a thread dump when this is going on. My assumption is that this type of problems aren't really a Zookeeper server issue, but Zookeeper client thread getting blocked which causes timeouts. There's one sign of this type of problem in issue #10418 . 
   
   For creating the thread dumps, please use `jstack`/`jcmd`/`kill -3`. The earlier thread dumps looked like they were created with the debugger. It's better to reproduce the issue and create thread dumps without the debugger attached since the JVM can behave differently in debugging mode. How were the previous thread dumps created?
   
   What version of Pulsar are you running? (can you reference a Git SHA for the version if it's based on master branch?)


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