[
https://issues.apache.org/jira/browse/KAFKA-16051?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Greg Harris reassigned KAFKA-16051:
-----------------------------------
Assignee: Octavian Ciubotaru
> Deadlock on connector initialization
> ------------------------------------
>
> Key: KAFKA-16051
> URL: https://issues.apache.org/jira/browse/KAFKA-16051
> Project: Kafka
> Issue Type: Bug
> Components: KafkaConnect
> Affects Versions: 2.6.3, 3.6.1
> Reporter: Octavian Ciubotaru
> Assignee: Octavian Ciubotaru
> Priority: Major
>
>
> Tested with Kafka 3.6.1 and 2.6.3.
> The only plugin installed is confluentinc-kafka-connect-jdbc-10.7.4.
> Stack trace for Kafka 3.6.1:
> {noformat}
> Found one Java-level deadlock:
> =============================
> "pool-3-thread-1":
> waiting to lock monitor 0x00007fbc88006300 (object 0x0000000091002aa0, a
> org.apache.kafka.connect.runtime.standalone.StandaloneHerder),
> which is held by "Thread-9"
> "Thread-9":
> waiting to lock monitor 0x00007fbc88008800 (object 0x000000009101ccd8, a
> org.apache.kafka.connect.storage.MemoryConfigBackingStore),
> which is held by "pool-3-thread-1"Java stack information for the threads
> listed above:
> ===================================================
> "pool-3-thread-1":
> at
> org.apache.kafka.connect.runtime.standalone.StandaloneHerder$ConfigUpdateListener.onTaskConfigUpdate(StandaloneHerder.java:516)
> - waiting to lock <0x0000000091002aa0> (a
> org.apache.kafka.connect.runtime.standalone.StandaloneHerder)
> at
> org.apache.kafka.connect.storage.MemoryConfigBackingStore.putTaskConfigs(MemoryConfigBackingStore.java:137)
> - locked <0x000000009101ccd8> (a
> org.apache.kafka.connect.storage.MemoryConfigBackingStore)
> at
> org.apache.kafka.connect.runtime.standalone.StandaloneHerder.updateConnectorTasks(StandaloneHerder.java:483)
> at
> org.apache.kafka.connect.runtime.standalone.StandaloneHerder.lambda$null$2(StandaloneHerder.java:229)
> at
> org.apache.kafka.connect.runtime.standalone.StandaloneHerder$$Lambda$692/0x0000000840557440.run(Unknown
> Source)
> at
> java.util.concurrent.Executors$RunnableAdapter.call(java.base@11.0.21/Executors.java:515)
> at
> java.util.concurrent.FutureTask.run(java.base@11.0.21/FutureTask.java:264)
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(java.base@11.0.21/ScheduledThreadPoolExecutor.java:304)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@11.0.21/ThreadPoolExecutor.java:1128)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@11.0.21/ThreadPoolExecutor.java:628)
> at java.lang.Thread.run(java.base@11.0.21/Thread.java:829)
> "Thread-9":
> at
> org.apache.kafka.connect.storage.MemoryConfigBackingStore.putTaskConfigs(MemoryConfigBackingStore.java:129)
> - waiting to lock <0x000000009101ccd8> (a
> org.apache.kafka.connect.storage.MemoryConfigBackingStore)
> at
> org.apache.kafka.connect.runtime.standalone.StandaloneHerder.updateConnectorTasks(StandaloneHerder.java:483)
> at
> org.apache.kafka.connect.runtime.standalone.StandaloneHerder.requestTaskReconfiguration(StandaloneHerder.java:255)
> - locked <0x0000000091002aa0> (a
> org.apache.kafka.connect.runtime.standalone.StandaloneHerder)
> at
> org.apache.kafka.connect.runtime.HerderConnectorContext.requestTaskReconfiguration(HerderConnectorContext.java:50)
> at
> org.apache.kafka.connect.runtime.WorkerConnector$WorkerConnectorContext.requestTaskReconfiguration(WorkerConnector.java:548)
> at
> io.confluent.connect.jdbc.source.TableMonitorThread.run(TableMonitorThread.java:86)
> Found 1 deadlock.
> {noformat}
> The jdbc source connector is loading tables from the database and updates the
> configuration once the list is available. The deadlock is very consistent in
> my environment, probably because the database is on the same machine.
> Maybe it is possible to avoid this situation by always locking the herder
> first and the config backing store second. From what I see,
> updateConnectorTasks sometimes is called before locking on herder and other
> times it is not.
>
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
