[
https://issues.apache.org/jira/browse/LOG4J2-1221?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Remko Popma resolved LOG4J2-1221.
---------------------------------
Resolution: Fixed
Fix Version/s: 2.5.1
[~sakumar] Since the problem seems to be in the Disruptor library
(https://github.com/LMAX-Exchange/disruptor/issues/138) there is a limit to
what can be done in log4j. I did notice that the problem occurred when an
extremely small ring buffer size (128) was configured and I strongly recommend
using the much larger default ring buffer size; I think that will vastly reduce
the chance of the problem happening again.
On top of that, you can now determine what happens when the ring buffer is
full. Please take a look at the [solution for LOG4J2
-1080|https://issues.apache.org/jira/browse/LOG4J2-1080?focusedCommentId=15069634&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15069634].
You can use this to create a workaround for your issue as follows.
For example, if you want to start logging events synchronously when the ring
buffer is full, you can do the following:
* set system property {{log4j2.AsyncEventRouter}} to value
{{com.mycompany.SampathKumarRouter}}
* compile the class below and add it to your classpath
{code}
package com.mycompany;
import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.core.async.AsyncEventRouter;
import org.apache.logging.log4j.core.async.EventRoute;
public class SampathKumarRouter implements AsyncEventRouter {
@Override
public EventRoute getRoute(final long backgroundThreadId, final Level
level, final int queueSize,
final int queueRemainingCapacity) {
// start logging synchronously when the queue is full, otherwise log
asynchronously
return queueRemainingCapacity == 0 ? EventRoute.SYNCHRONOUS :
EventRoute.ENQUEUE;
}
}
{code}
> Dead lock observed in BlockingWaitStrategy in Log 4J
> ----------------------------------------------------
>
> Key: LOG4J2-1221
> URL: https://issues.apache.org/jira/browse/LOG4J2-1221
> Project: Log4j 2
> Issue Type: Bug
> Components: Core
> Affects Versions: 2.2
> Environment: log4J Version : 2.2 Disruptor Version : 3.3.2
> Ring Buffer Size : 128
> OS Version :
> cat /etc/release
> Oracle Solaris 11.2 X86
> Java Version
> java version "1.7.0_45"
> Java(TM) SE Runtime Environment (build 1.7.0_45-b18)
> Java HotSpot(TM) Server VM (build 24.45-b08, mixed mode)
> Reporter: Sampath Kumar
> Priority: Critical
> Labels: patch
> Fix For: 2.5.1
>
> Attachments: log4j2-test.xml
>
>
> We have seen this behavior in during high load. Where Logging Got Stropped
> and Application Went to not responsive state.
> log4J Version : 2.2 Disruptor Version : 3.3.2
> Ring Buffer Size : 128
> Producer(Multiples Threads) and Consumer Threads(Single Thread As per Log 4J
> Configuration) Started Waiting on each other.
> Here is the one of the Trace from Thread Dump:
> Producer :
> "[ACTIVE] ExecuteThread: '7' for queue: 'weblogic.kernel.Default
> (self-tuning)'" TIMED_WAITING
> sun.misc.Unsafe.park(Native Method)
> java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:349)
> com.lmax.disruptor.MultiProducerSequencer.next(MultiProducerSequencer.java:136)
> com.lmax.disruptor.MultiProducerSequencer.next(MultiProducerSequencer.java:105)
> com.lmax.disruptor.RingBuffer.publishEvent(RingBuffer.java:444)
> com.lmax.disruptor.dsl.Disruptor.publishEvent(Disruptor.java:256)
> org.apache.logging.log4j.core.async.AsyncLogger.logMessage(AsyncLogger.java:285)
> org.apache.logging.log4j.spi.AbstractLogger.logMessage(AbstractLogger.java:722)
> org.apache.logging.log4j.spi.AbstractLogger.logIfEnabled(AbstractLogger.java:693)
> org.apache.logging.log4j.jcl.Log4jLog.debug(Log4jLog.java:81)
> Consumer Thread :
> "AsyncLogger-1" waiting for lock
> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject@5d972983
> WAITING
> sun.misc.Unsafe.park(Native Method)
> java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2043)
> com.lmax.disruptor.BlockingWaitStrategy.waitFor(BlockingWaitStrategy.java:45)
> com.lmax.disruptor.ProcessingSequenceBarrier.waitFor(ProcessingSequenceBarrier.java:55)
> com.lmax.disruptor.BatchEventProcessor.run(BatchEventProcessor.java:123)
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
> java.lang.Thread.run(Thread.java:744)
> Is this is known issue which got already fixed in recent build ?
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