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https://issues.apache.org/jira/browse/LOG4J2-1221?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15054277#comment-15054277
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Sampath Kumar commented on LOG4J2-1221:
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We need to check implementation of RingBuffer to confirm behaviour of
RingBuffer.tryPublishEvent() drop the event. If the same behaviour as expected
by LOG4J2-1080 we can achieve using this API, I recommend to use this API if
its return false drop the event or to log the event synchronously (send it to
the appender directly).This solves both Dead Lock Issue and Buffer Full
Performance issue.
I agree that this buffer size is too small. This can cause performance issue
but no one accept application to go for dead lock !!. We will modify it to
default 256.
Regards,
Sakumar
> 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
>
> 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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