Maxence Dunnewind created AMQ-6482:
--------------------------------------
Summary: 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
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
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
