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https://issues.apache.org/jira/browse/AMQ-9482?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17849248#comment-17849248
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Tom Tichy commented on AMQ-9482:
--------------------------------
Hi,
I did add the `soTimeout` and `soWriteTimeout`, but alas no joy.
I have a better thread dump with about 11.5k identical threads that are in the
WAITING state
Fastthread.io analysis says
{quote}
h1. 11440 threads with same stack trace
!https://fastthread.io/assets/globally-shared/images/icon-error.svg! 11440
threads are WAITING on *_park()_* method in *_jdk.internal.misc.Unsafe_* file
and they all have same stack trace. If multiple threads exhibit same stack
trace, you might want to examine their stack trace. (Note: If your application
is unresponsive or poorly responding, it might be caused because these threads).
{panel}
h2. {color:#cc3300}ActiveMQ BrokerService[localhost] Task-68826{color}
PRIORITY : 5
THREAD ID : 0X00007F1E3010FB90
NATIVE ID : 0XE3ABE
NATIVE ID (DECIMAL) : 932542
STATE : TIMED_WAITING
stackTrace:
java.lang.Thread.State: TIMED_WAITING (parking)
at jdk.internal.misc.Unsafe.park({color:#000080}java.base@{*}17.0.9/Native
Method{*}{color}{*}){*}
- parking to wait for *<0x0000000700232d10>* (a
java.util.concurrent.SynchronousQueue$TransferStack)
at
java.util.concurrent.locks.LockSupport.parkNanos({color:#000080}java.base@{*}17.0.9/LockSupport.java:252{*}{color}{*}){*}
at
java.util.concurrent.SynchronousQueue$TransferStack.transfer({color:#000080}java.base@{*}17.0.9/SynchronousQueue.java:401{*}{color}{*}){*}
at
java.util.concurrent.SynchronousQueue.poll({color:#000080}java.base@{*}17.0.9/SynchronousQueue.java:903{*}{color}{*}){*}
at
java.util.concurrent.ThreadPoolExecutor.getTask({color:#000080}java.base@{*}17.0.9/ThreadPoolExecutor.java:1061{*}{color}{*}){*}
at
java.util.concurrent.ThreadPoolExecutor.runWorker({color:#000080}java.base@{*}17.0.9/ThreadPoolExecutor.java:1122{*}{color}{*}){*}
at
java.util.concurrent.ThreadPoolExecutor$Worker.run({color:#000080}java.base@{*}17.0.9/ThreadPoolExecutor.java:635{*}{color}{*}){*}
at
java.lang.Thread.run({color:#000080}java.base@{*}17.0.9/Thread.java:840{*}{color}{*}){*}
Locked ownable synchronizers:
- None{panel}
{quote}
Here is another piece of information that may be relevant. The devices that
connect to our brokers do something silly and open a new MQTT connection
everytime they want to send something. The MQTT spec allows this and ActiveMQ
dutifully logs
{code:java}
WARN | Stealing link for clientId xxxx{code}
[^thread_dump.txt]
> Broker crashes after runaway threads spawn
> ------------------------------------------
>
> Key: AMQ-9482
> URL: https://issues.apache.org/jira/browse/AMQ-9482
> Project: ActiveMQ Classic
> Issue Type: Bug
> Components: Broker
> Affects Versions: 5.17.6, 6.0.1
> Environment: Bitnami created AMI in AWS
> Reporter: Tom Tichy
> Priority: Major
> Attachments: activemq.tdump, brokerInfo-after-crash-redacted.json,
> thread_dump.txt
>
>
> Running on Bitnami created AMI in AWS. The broker has about 7000 devices
> connected via MQTT. Each devices has its own topic name.
> Broker stays up for about 4-5 days before being hobbled and unable to create
> any new tasks/accept any new connections.
> (There is identical setup for staging environment with about 100 devices
> connected. It runs without any issues.)
> I have troubleshot the cause to be the systemd task limit. The current
> `TasksMax` is 18100. When running normally, the number of tasks is about 300.
> Then (every 4-5 days) there is a quick spike to the max 18100 tasks and it
> stays there never coming back down. The result is that the broker just sits
> there, does nothing useful and keeps logging the following message
>
> {code:java}
> [659914.788s][warning][os,thread] Failed to start thread "Unknown thread" -
> pthread_create failed (EAGAIN) for attributes: stacksize: 1024k, g
> uardsize: 0k, detached.
> [659914.788s][warning][os,thread] Failed to start the native thread for
> java.lang.Thread "ActiveMQ BrokerService[localhost] Task-281805"
> ERROR | Scheduled task error
> java.lang.OutOfMemoryError: unable to create native thread: possibly out of
> memory or process/resource limits reached
> at java.lang.Thread.start0(Native Method) ~[?:?]
> at java.lang.Thread.start(Thread.java:809) ~[?:?]
> at
> java.util.concurrent.ThreadPoolExecutor.addWorker(ThreadPoolExecutor.java:945)
> ~[?:?]
> at
> java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1364)
> ~[?:?]
> at
> org.apache.activemq.thread.TaskRunnerFactory.execute(TaskRunnerFactory.java:173)
> ~[activemq-client-6.0.1.jar:6.0.1]
> at
> org.apache.activemq.thread.TaskRunnerFactory.execute(TaskRunnerFactory.java:165)
> ~[activemq-client-6.0.1.jar:6.0.1]
> at org.apache.activemq.broker.region.Topic$7.run(Topic.java:820)
> ~[activemq-broker-6.0.1.jar:6.0.1]
> at
> org.apache.activemq.thread.SchedulerTimerTask.run(SchedulerTimerTask.java:39)
> ~[activemq-client-6.0.1.jar:6.0.1]
> at java.util.TimerThread.mainLoop(Timer.java:566) ~[?:?]
> at java.util.TimerThread.run(Timer.java:516) ~[?:?]
> Exception in thread "ActiveMQ Broker[localhost] Scheduler"
> java.lang.OutOfMemoryError: unable to create native thread: possibly out of
> memory or process/resource limits reached
> at java.base/java.lang.Thread.start0(Native Method)
> at java.base/java.lang.Thread.start(Thread.java:809)
> at
> java.base/java.util.concurrent.ThreadPoolExecutor.addWorker(ThreadPoolExecutor.java:945)
> at
> java.base/java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1364)
> at
> org.apache.activemq.thread.TaskRunnerFactory.execute(TaskRunnerFactory.java:173)
> at
> org.apache.activemq.thread.TaskRunnerFactory.execute(TaskRunnerFactory.java:165)
> at org.apache.activemq.broker.region.Topic$7.run(Topic.java:820)
> at
> org.apache.activemq.thread.SchedulerTimerTask.run(SchedulerTimerTask.java:39)
> at java.base/java.util.TimerThread.mainLoop(Timer.java:566)
> at java.base/java.util.TimerThread.run(Timer.java:516)
> {code}
>
> The start command is
> {code:java}
> /opt/bitnami/java/bin/java -Xms2G -Xmx4G
> -Djava.util.logging.config.file=logging.properties
> -Djava.security.auth.login.config=/opt/bitnami/activemq/conf/login.config
> -Dorg.apache.activemq.UseDedicatedTaskRunner=false
> -Dcom.sun.management.jmxremote -Djava.awt.headless=true
> -Djava.io.tmpdir=/opt/bitnami/activemq/tmp --add-reads=java.xml=java.logging
> --add-opens java.base/java.security=ALL-UNNAMED --add-opens
> java.base/java.net=ALL-UNNAMED --add-opens java.base/java.lang=ALL-UNNAMED
> --add-opens java.base/java.util=ALL-UNNAMED --add-opens
> java.naming/javax.naming.spi=ALL-UNNAMED --add-opens
> java.rmi/sun.rmi.transport.tcp=ALL-UNNAMED --add-opens
> java.base/java.util.concurrent=ALL-UNNAMED --add-opens
> java.base/java.util.concurrent.atomic=ALL-UNNAMED
> --add-exports=java.base/sun.net.www.protocol.http=ALL-UNNAMED
> --add-exports=java.base/sun.net.www.protocol.https=ALL-UNNAMED
> --add-exports=java.base/sun.net.www.protocol.jar=ALL-UNNAMED
> --add-exports=jdk.xml.dom/org.w3c.dom.html=ALL-UNNAMED
> --add-exports=jdk.naming.rmi/com.sun.jndi.url.rmi=ALL-UNNAMED
> -Dactivemq.classpath=/opt/bitnami/activemq/conf:/opt/bitnami/activemq/../lib/:
> -Dactivemq.home=/opt/bitnami/activemq -Dactivemq.base=/opt/bitnami/activemq
> -Dactivemq.conf=/opt/bitnami/activemq/conf
> -Dactivemq.data=/opt/bitnami/activemq/data
> -Djolokia.conf=file:/opt/bitnami/activemq/conf/jolokia-access.xml -jar
> /opt/bitnami/activemq/bin/activemq.jar start {code}
> During the error condition, I am able to collect broker information via
> jolokia: [^brokerInfo-after-crash-redacted.json]
>
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