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https://issues.apache.org/jira/browse/AMQ-6482?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15634132#comment-15634132
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Timothy Bish commented on AMQ-6482:
-----------------------------------
Seems reasonable that these calls shouldn't block but we need to at least try
and throw an error if the send can't complete to break the connection, so maybe
something like:
{code}
@Override
public void sendToStomp(StompFrame command) throws IOException {
try {
session.getRemote().sendStringByFuture(command.format()).get(30,
TimeUnit.SECONDS);
} catch (Exception e) {
throw IOExceptionSupport.create(e);
}
}
{code}
> Possible thread leak ?
> ----------------------
>
> Key: AMQ-6482
> URL: https://issues.apache.org/jira/browse/AMQ-6482
> Project: ActiveMQ
> Issue Type: Bug
> Components: Broker
> Affects Versions: 5.14.1
> Reporter: Maxence Dunnewind
> Labels: threading
> Attachments: thread_dump
>
>
> We have an activemq broker running for ~ 24 hours, handling ~ 100k topics and
> up to 8k connections (for ~ 24k consumers).
> Looking at my graph, I see that I get a big increase of threads count
> happended (in 4 steps, ~ 500 more threads each time) as shown here :
> https://snapshot.raintank.io/dashboard/snapshot/ExUb4pgNYnmBo92JgbZrvJ6fiBm3PNrI
> However, even if the traffic dropped in the night, the thread count never
> decreased and is still ~ 2500.
> I checked a thread dump and it looks like (full dump attached) :
> ```
> # grep Thread.State thread_dump |awk '{ print $2 }' |sort|uniq -c
> 26 RUNNABLE
> 70 TIMED_WAITING
> 2446 WAITING
> ```
> Mhh, so many WAITING threads, let's check why :
> ```
> # grep 'parking to' thread_dump |cut -d '>' -f 2 |sort |uniq -c
> 1 (a java.util.concurrent.CountDownLatch$Sync)
> 1308 (a
> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
> 1159 (a java.util.concurrent.locks.ReentrantLock$NonfairSync)
> 41 (a java.util.concurrent.SynchronousQueue$TransferStack)
> ```
> I'm not a big java expert but seems a bit unexpected behavior to me.
> For various reason (big number of topics etc ) we use custom GC config, here
> it is :
> ```
> ACTIVEMQ_OPTS_MEMORY="-Xms128M -Xmx10G -Xloggc:/home/log/activemq/gc.log
> -XX:+PrintGC -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+UseG1GC
> -XX:InitiatingHeapOccupancyPercent=75 -XX:NewRatio=4"
> ```
> Maxence
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