Memory leak exception while stopping the datahub

[Former Member]

Hi Experts,

I am getting below SEVERE errors while shutting down the datahub server 6.4.0.0,

 SEVERE: The web application [/datahub-webapp] appears to have started a thread named [oracle.jdbc.driver.BlockSource.ThreadedCachingBlockSource.BlockReleaser] but has failed to stop it. This is very likely to create a memory leak.
 Nov 14, 2018 8:57:32 AM org.apache.catalina.loader.WebappClassLoaderBase checkThreadLocalMapForLeaks
 SEVERE: The web application [/datahub-webapp] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@169da8a1]) and a value of type [scala.concurrent.forkjoin.ForkJoinPool.Submitter] (value [scala.concurrent.forkjoin.ForkJoinPool$Submitter@75b85468]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.

Anyone have any idea about this error?

Thanks, Niket

[former_member224482]

This error can be safely ignored for application [/datahub-webapp].

Un-deployment memory leaks only matters if the application [/datahub-webapp] would be re-deployed without restarting the tomcat. As the tomcat is shutdown, all those leaks are gone.

[Former Member]

Hi Justin,

I was expecting this patch one ;), we have planned to do this as well on next week. Can you please share the commands which you are using to stnd stop the tomcat server?

Thanks, Niket

[former_member333910]

"Can you please share the commands which you are using to stnd stop the tomcat server?"

You can just use the standard Tomcat commands. For details see the "Start Up Tomcat" and "Shut Down Tomcat" sections of the Tomcat docs.

https://tomcat.apache.org/tomcat-8.5-doc/RUNNING.txt

[former_member333910]

Hi Niket,

Firstly, I highly suggest upgrading from 6.4.0.0 to at least the latest 6.4.0.x patch version. Many important issues have been fixed since the initial 6.4.0.0 release.

I do not think the SEVERE errors logged during shutdown are a concern. I expect that you will find that Tomcat has completely shut down and not left a running process.

Data Hub has been tested in long-running, high volume environments and we have not seen any true memory leaks reported.