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Posted to jira@kafka.apache.org by "Konstantine Karantasis (Jira)" <ji...@apache.org> on 2021/02/25 08:02:00 UTC
[jira] [Commented] (KAFKA-7421) Deadlock in Kafka Connect
[ https://issues.apache.org/jira/browse/KAFKA-7421?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17290761#comment-17290761 ]
Konstantine Karantasis commented on KAFKA-7421:
-----------------------------------------------
The suggested fix suggested by [~ivanyu] seems plausible. The method locking seems to have been an oversight given the fine grain locking based on classloader instance and requested class name.
I've extended the PR that added a test with the probable fix here: https://github.com/apache/kafka/pull/8259
> Deadlock in Kafka Connect
> -------------------------
>
> Key: KAFKA-7421
> URL: https://issues.apache.org/jira/browse/KAFKA-7421
> Project: Kafka
> Issue Type: Bug
> Components: KafkaConnect
> Affects Versions: 2.0.0
> Reporter: Maciej Bryński
> Assignee: Konstantine Karantasis
> Priority: Major
>
> I'm getting this deadlock on half of Kafka Connect runs when having two different types connectors (in this configuration it's debezium and hdfs).
> Thread 1:
> {code}
> "pool-22-thread-2@4748" prio=5 tid=0x4d nid=NA waiting for monitor entry
> java.lang.Thread.State: BLOCKED
> waiting for pool-22-thread-1@4747 to release lock on <0x1423> (a org.apache.kafka.connect.runtime.isolation.PluginClassLoader)
> at org.apache.kafka.connect.runtime.isolation.PluginClassLoader.loadClass(PluginClassLoader.java:91)
> at org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader.loadClass(DelegatingClassLoader.java:367)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
> at java.lang.Class.forName0(Class.java:-1)
> at java.lang.Class.forName(Class.java:348)
> at org.apache.kafka.common.config.ConfigDef.parseType(ConfigDef.java:715)
> at org.apache.kafka.connect.runtime.ConnectorConfig.enrich(ConnectorConfig.java:295)
> at org.apache.kafka.connect.runtime.ConnectorConfig.<init>(ConnectorConfig.java:200)
> at org.apache.kafka.connect.runtime.ConnectorConfig.<init>(ConnectorConfig.java:194)
> at org.apache.kafka.connect.runtime.Worker.startConnector(Worker.java:233)
> at org.apache.kafka.connect.runtime.distributed.DistributedHerder.startConnector(DistributedHerder.java:916)
> at org.apache.kafka.connect.runtime.distributed.DistributedHerder.access$1300(DistributedHerder.java:111)
> at org.apache.kafka.connect.runtime.distributed.DistributedHerder$15.call(DistributedHerder.java:932)
> at org.apache.kafka.connect.runtime.distributed.DistributedHerder$15.call(DistributedHerder.java:928)
> at java.util.concurrent.FutureTask.run(FutureTask.java:266)
> at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
> at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
> at java.lang.Thread.run(Thread.java:748)
> {code}
> Thread 2:
> {code}
> "pool-22-thread-1@4747" prio=5 tid=0x4c nid=NA waiting for monitor entry
> java.lang.Thread.State: BLOCKED
> blocks pool-22-thread-2@4748
> waiting for pool-22-thread-2@4748 to release lock on <0x1421> (a org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:406)
> at org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader.loadClass(DelegatingClassLoader.java:358)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:411)
> - locked <0x1424> (a java.lang.Object)
> at org.apache.kafka.connect.runtime.isolation.PluginClassLoader.loadClass(PluginClassLoader.java:104)
> - locked <0x1423> (a org.apache.kafka.connect.runtime.isolation.PluginClassLoader)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
> at io.debezium.transforms.ByLogicalTableRouter.<clinit>(ByLogicalTableRouter.java:57)
> at java.lang.Class.forName0(Class.java:-1)
> at java.lang.Class.forName(Class.java:348)
> at org.apache.kafka.common.config.ConfigDef.parseType(ConfigDef.java:715)
> at org.apache.kafka.connect.runtime.ConnectorConfig.enrich(ConnectorConfig.java:295)
> at org.apache.kafka.connect.runtime.ConnectorConfig.<init>(ConnectorConfig.java:200)
> at org.apache.kafka.connect.runtime.ConnectorConfig.<init>(ConnectorConfig.java:194)
> at org.apache.kafka.connect.runtime.Worker.startConnector(Worker.java:233)
> at org.apache.kafka.connect.runtime.distributed.DistributedHerder.startConnector(DistributedHerder.java:916)
> at org.apache.kafka.connect.runtime.distributed.DistributedHerder.access$1300(DistributedHerder.java:111)
> at org.apache.kafka.connect.runtime.distributed.DistributedHerder$15.call(DistributedHerder.java:932)
> at org.apache.kafka.connect.runtime.distributed.DistributedHerder$15.call(DistributedHerder.java:928)
> at java.util.concurrent.FutureTask.run(FutureTask.java:266)
> at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
> at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
> at java.lang.Thread.run(Thread.java:748)
> {code}
> I'm using official Confluent Docker images.
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