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Flavio Pompermaier commented on FLINK-20614: -------------------------------------------- Could this problem be related also to a missing proper close for Java Tasks as in FLINK-20333? > Registered sql drivers not deregistered after task finished in session cluster > ------------------------------------------------------------------------------ > > Key: FLINK-20614 > URL: https://issues.apache.org/jira/browse/FLINK-20614 > Project: Flink > Issue Type: Bug > Components: Connectors / JDBC, Runtime / Task > Affects Versions: 1.12.0, 1.13.0 > Reporter: Kezhu Wang > Priority: Major > > {{DriverManager}} keeps registered drivers in its internal data structures > which prevents they from gc after task finished. I confirm it in standalone > session cluster by observing that {{ChildFirstClassLoader}} could not be > reclaimed after several {{GC.run}}, it should exist in all session clusters. > Tomcat documents > [this|https://ci.apache.org/projects/tomcat/tomcat85/docs/jndi-datasource-examples-howto.html#DriverManager,_the_service_provider_mechanism_and_memory_leaks] > and fixes/circumvents this with > [JdbcLeakPrevention|https://github.com/apache/tomcat/blob/master/java/org/apache/catalina/loader/JdbcLeakPrevention.java#L30]. > Should we solve this in runtime ? Or treat it as connector and clients' > responsibility to solve it using > {{RuntimeContext.registerUserCodeClassLoaderReleaseHookIfAbsent}} or similar ? > Personally, it would be nice to solve in runtime as a catch-all to avoid > memory-leaking and provide consistent behavior to clients cross per-job and > session mode. -- This message was sent by Atlassian Jira (v8.3.4#803005)