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https://issues.apache.org/jira/browse/CASSANDRA-7743?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14096638#comment-14096638
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Benedict commented on CASSANDRA-7743:
-------------------------------------
We're conflating two pools maybe :)
I mean the "pool" of memory the thread can allocate from. So, to confirm I have
this right, if you have two threads A and B, A only allocating and B only
releasing, you would get memory accumulating up to max pool size in B, and A
always allocating new memory?
> Possible C* OOM issue during long running test
> ----------------------------------------------
>
> Key: CASSANDRA-7743
> URL: https://issues.apache.org/jira/browse/CASSANDRA-7743
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Environment: Google Compute Engine, n1-standard-1
> Reporter: Pierre Laporte
> Assignee: Benedict
> Fix For: 2.1.0
>
>
> During a long running test, we ended up with a lot of
> "java.lang.OutOfMemoryError: Direct buffer memory" errors on the Cassandra
> instances.
> Here is an example of stacktrace from system.log :
> {code}
> ERROR [SharedPool-Worker-1] 2014-08-11 11:09:34,610 ErrorMessage.java:218 -
> Unexpected exception during request
> java.lang.OutOfMemoryError: Direct buffer memory
> at java.nio.Bits.reserveMemory(Bits.java:658) ~[na:1.7.0_25]
> at java.nio.DirectByteBuffer.<init>(DirectByteBuffer.java:123)
> ~[na:1.7.0_25]
> at java.nio.ByteBuffer.allocateDirect(ByteBuffer.java:306)
> ~[na:1.7.0_25]
> at io.netty.buffer.PoolArena$DirectArena.newChunk(PoolArena.java:434)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at io.netty.buffer.PoolArena.allocateNormal(PoolArena.java:179)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at io.netty.buffer.PoolArena.allocate(PoolArena.java:168)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at io.netty.buffer.PoolArena.allocate(PoolArena.java:98)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at
> io.netty.buffer.PooledByteBufAllocator.newDirectBuffer(PooledByteBufAllocator.java:251)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at
> io.netty.buffer.AbstractByteBufAllocator.directBuffer(AbstractByteBufAllocator.java:155)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at
> io.netty.buffer.AbstractByteBufAllocator.directBuffer(AbstractByteBufAllocator.java:146)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at
> io.netty.buffer.AbstractByteBufAllocator.ioBuffer(AbstractByteBufAllocator.java:107)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at
> io.netty.channel.AdaptiveRecvByteBufAllocator$HandleImpl.allocate(AdaptiveRecvByteBufAllocator.java:104)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at
> io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:112)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at
> io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:507)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at
> io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:464)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at
> io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:378)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:350)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at
> io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)
> ~[netty-all-4.0.20.Final.jar:4.0.20.Final]
> at java.lang.Thread.run(Thread.java:724) ~[na:1.7.0_25]
> {code}
> The test consisted of a 3-nodes cluster of n1-standard-1 GCE instances (1
> vCPU, 3.75 GB RAM) running cassandra-2.1.0-rc5, and a n1-standard-2 instance
> running the test.
> After ~2.5 days, several requests start to fail and we see the previous
> stacktraces in the system.log file.
> The output from linux ‘free’ and ‘meminfo’ suggest that there is still memory
> available.
> {code}
> $ free -m
> total used free shared buffers cached
> Mem: 3702 3532 169 0 161 854
> -/+ buffers/cache: 2516 1185
> Swap: 0 0 0
> $ head -n 4 /proc/meminfo
> MemTotal: 3791292 kB
> MemFree: 173568 kB
> Buffers: 165608 kB
> Cached: 874752 kB
> {code}
> These errors do not affect all the queries we run. The cluster is still
> responsive but is unable to display tracing information using cqlsh :
> {code}
> $ ./bin/nodetool --host 10.240.137.253 status duration_test
> Datacenter: DC1
> ===============
> Status=Up/Down
> |/ State=Normal/Leaving/Joining/Moving
> -- Address Load Tokens Owns (effective) Host ID
> Rack
> UN 10.240.98.27 925.17 KB 256 100.0%
> 41314169-eff5-465f-85ea-d501fd8f9c5e RAC1
> UN 10.240.137.253 1.1 MB 256 100.0%
> c706f5f9-c5f3-4d5e-95e9-a8903823827e RAC1
> UN 10.240.72.183 896.57 KB 256 100.0%
> 15735c4d-98d4-4ea4-a305-7ab2d92f65fc RAC1
> $ echo 'tracing on; select count(*) from duration_test.ints;' | ./bin/cqlsh
> 10.240.137.253
> Now tracing requests.
> count
> -------
> 9486
> (1 rows)
> Statement trace did not complete within 10 seconds
> {code}
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