cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Benedict (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-9549) Memory leak
Date Thu, 04 Jun 2015 20:56:39 GMT


Benedict commented on CASSANDRA-9549:

Thanks. Unfortunately that does not seem to be the complete log history. It would help a great
deal to have logs from when the node actually started up.

I can make an educated guess, though: it looks like the node was OOMing due to normal operational
reasons (or perhaps some other issue, we cannot say), and we recently modified behaviour in
this scenario to trigger a shutdown of the host. Unfortunately, it seems that the OOM is somehow
delaying the shutdown from completing, or perhaps there is some other issue. Certainly the
JVM thinks it is shutting down.

The strange thing is that the shutdown hook must still have been run, since that is the only
way the executor service could be shutdown, only we ask the shutdown hook to be removed in
this event.

More complete logs would help us.

Increasing your heap space may fix the underlying problem. It may be that there is another
underlying issue causing your heap to explode. To establish this we would need a heap dump
during one of these events. If, however, you make extensive use of CQL row deletions, or CQL
collections and perform overwrites of the entire collection, it may be that you are encountering
CASSANDRA-9486, in which case a patch is available for that, and will be fixed in 2.1.6 to
be released shortly.

> Memory leak 
> ------------
>                 Key: CASSANDRA-9549
>                 URL:
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>         Environment: Cassandra 2.1.5. 9 node cluster in EC2 (m1.large nodes, 2 cores
7.5G memory, 800G platter for cassandra data, root partition and commit log are on SSD EBS
with sufficient IOPS), 3 nodes/availablity zone, 1 replica/zone
> JVM: /usr/java/jdk1.8.0_40/jre/bin/java 
> JVM Flags besides CP: -ea -javaagent:/usr/share/cassandra/lib/jamm-0.3.0.jar -XX:+CMSClassUnloadingEnabled
-XX:+UseThreadPriorities -XX:ThreadPriorityPolicy=42 -Xms2G -Xmx2G -Xmn200M -XX:+HeapDumpOnOutOfMemoryError
-Xss256k -XX:StringTableSize=1000003 -XX:+UseParNewGC -XX:+UseConcMarkSweepGC -XX:+CMSParallelRemarkEnabled
-XX:SurvivorRatio=8 -XX:MaxTenuringThreshold=1 -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly
-XX:+UseTLAB -XX:CompileCommandFile=/etc/cassandra/conf/hotspot_compiler -XX:CMSWaitDuration=10000
-XX:+CMSParallelInitialMarkEnabled -XX:+CMSEdenChunksRecordAlways -XX:CMSWaitDuration=10000
-Dlogback.configurationFile=logback.xml -Dcassandra.logdir=/var/log/cassandra -Dcassandra.storagedir=
> Kernel: Linux 2.6.32-504.16.2.el6.x86_64 #1 SMP x86_64 x86_64 x86_64 GNU/Linux
>            Reporter: Ivar Thorson
>            Priority: Critical
>             Fix For: 2.1.x
>         Attachments: c4_system.log, cassandra.yaml, cpu-load.png, memoryuse.png, ref-java-errors.jpeg,
suspect.png, two-loads.png
> We have been experiencing a severe memory leak with Cassandra 2.1.5 that, over the period
of a couple of days, eventually consumes all of the available JVM heap space, putting the
JVM into GC hell where it keeps trying CMS collection but can't free up any heap space. This
pattern happens for every node in our cluster and is requiring rolling cassandra restarts
just to keep the cluster running. We have upgraded the cluster per Datastax docs from the
2.0 branch a couple of months ago and have been using the data from this cluster for more
than a year without problem.
> As the heap fills up with non-GC-able objects, the CPU/OS load average grows along with
it. Heap dumps reveal an increasing number of java.util.concurrent.ConcurrentLinkedQueue$Node
objects. We took heap dumps over a 2 day period, and watched the number of Node objects go
from 4M, to 19M, to 36M, and eventually about 65M objects before the node stops responding.
The screen capture of our heap dump is from the 19M measurement.
> Load on the cluster is minimal. We can see this effect even with only a handful of writes
per second. (See attachments for Opscenter snapshots during very light loads and heavier loads).
Even with only 5 reads a sec we see this behavior.
> Log files show repeated errors in and and "LEAK detected" messages:
> {code}
> ERROR [CompactionExecutor:557] 2015-06-01 18:27:36,978 - Error when closing
> java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask@32680b31
rejected from org.apache.cassandra.concurrent.DebuggableScheduledThreadPoolExecutor@573464d6[Terminated,
pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 1644]
> {code}
> {code}
> ERROR [Reference-Reaper:1] 2015-06-01 18:27:37,083 - LEAK DETECTED: a reference
(org.apache.cassandra.utils.concurrent.Ref$State@74b5df92) to class$DescriptorTypeTidy@2054303604:/data2/data/ourtablegoeshere-ka-1151
was not released before the reference was garbage collected
> {code}
> This might be related to [CASSANDRA-8723]?

This message was sent by Atlassian JIRA

View raw message