Gareth Davis created AVRO-1407:
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Summary: NettyTransceiver can cause a infinite loop when slow to
connect
Key: AVRO-1407
URL: https://issues.apache.org/jira/browse/AVRO-1407
Project: Avro
Issue Type: Bug
Components: java
Affects Versions: 1.7.5, 1.7.6
Reporter: Gareth Davis
When a new {{NettyTransceiver}} is created it forces the channel to be
allocated and connected to the remote host. it waits for the connectTimeout ms
on the [connect channel
future|https://github.com/apache/avro/blob/1579ab1ac95731630af58fc303a07c9bf28541d6/lang/java/ipc/src/main/java/org/apache/avro/ipc/NettyTransceiver.java#L271]
this is obivously a good thing it's only that on being unsuccessful, ie
{{!channelFuture.isSuccess()}} an exception is thrown and the call to the
constructor fails with an {{IOException}}, but has the potential to leave a
active channel associated with the {{ChannelFactory}}
The problem is that a Netty {{NioClientSocketChannelFactory}} will not shutdown
if there are active channels still around and if you have supplied the
{{ChannelFactory}} to the {{NettyTransceiver}} then you will not be able to
cancel it by calling {{ChannelFactory.releaseExternalResources()}} like the
[Flume Avro RPC client
does|https://github.com/apache/flume/blob/b8cf789b8509b1e5be05dd0b0b16c5d9af9698ae/flume-ng-sdk/src/main/java/org/apache/flume/api/NettyAvroRpcClient.java#L158].
In order to recreate this you need a very laggy network, where the connect
attempt takes longer than the connect timeout but does actually work, this very
hard to organise in a test case, although I do have a test setup using vagrant
VM's that recreates this everytime, using the Flume RPC client and server.
The following stack is from a production system, it won't ever leave recover
until the channel is disconnected (by forcing a disconnect at the remote host)
or restarting the JVM.
{noformat:title=Production stack trace}
"TLOG-0" daemon prio=10 tid=0x00007f581c7be800 nid=0x39a1 waiting on condition
[0x00007f57ef9f2000]
java.lang.Thread.State: TIMED_WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
parking to wait for <0x00000007218b16e0> (a
java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:196)
at
java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2025)
at
java.util.concurrent.ThreadPoolExecutor.awaitTermination(ThreadPoolExecutor.java:1253)
at org.jboss.netty.util.internal.ExecutorUtil.terminate(ExecutorUtil.java:103)
at
org.jboss.netty.channel.socket.nio.AbstractNioWorkerPool.releaseExternalResources(AbstractNioWorkerPool.java:80)
at
org.jboss.netty.channel.socket.nio.NioClientSocketChannelFactory.releaseExternalResources(NioClientSocketChannelFactory.java:181)
at
org.apache.flume.api.NettyAvroRpcClient.connect(NettyAvroRpcClient.java:142)
at
org.apache.flume.api.NettyAvroRpcClient.connect(NettyAvroRpcClient.java:101)
at
org.apache.flume.api.NettyAvroRpcClient.configure(NettyAvroRpcClient.java:564)
locked <0x00000006c30ae7b0> (a org.apache.flume.api.NettyAvroRpcClient)
at org.apache.flume.api.RpcClientFactory.getInstance(RpcClientFactory.java:88)
at
org.apache.flume.api.LoadBalancingRpcClient.createClient(LoadBalancingRpcClient.java:214)
at
org.apache.flume.api.LoadBalancingRpcClient.getClient(LoadBalancingRpcClient.java:205)
locked <0x00000006a97b18e8> (a org.apache.flume.api.LoadBalancingRpcClient)
at
org.apache.flume.api.LoadBalancingRpcClient.appendBatch(LoadBalancingRpcClient.java:95)
at
com.ean.platform.components.tlog.client.service.AvroRpcEventRouter$1.call(AvroRpcEventRouter.java:45)
at
com.ean.platform.components.tlog.client.service.AvroRpcEventRouter$1.call(AvroRpcEventRouter.java:43)
{noformat}
The solution is very simple, and a patch should be along in a moment.
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