Yu Li created HBASE-16429:
-----------------------------
Summary: FSHLog: deadlock if rollWriter called when ring buffer
filled with appends
Key: HBASE-16429
URL: https://issues.apache.org/jira/browse/HBASE-16429
Project: HBase
Issue Type: Bug
Affects Versions: 1.2.2, 1.1.2
Reporter: Yu Li
Assignee: Yu Li
Priority: Critical
Recently we experienced an online problem that all handlers are stuck. Checking
the jstack we could see all handler threads waiting for RingBuffer.next, while
the single ring buffer consumer dead waiting for {{safePointReleasedLatch}} to
count down:
{noformat}
Normal handler thread:
"B.defaultRpcServer.handler=126,queue=9,port=16020" daemon prio=10
tid=0x00007efd4b44f800 nid=0x15f29 runnable [0x00007efd3db7b000]
java.lang.Thread.State: TIMED_WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
at
java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:349)
at
com.lmax.disruptor.MultiProducerSequencer.next(MultiProducerSequencer.java:136)
at
com.lmax.disruptor.MultiProducerSequencer.next(MultiProducerSequencer.java:105)
at com.lmax.disruptor.RingBuffer.next(RingBuffer.java:246)
at
org.apache.hadoop.hbase.regionserver.wal.FSHLog.append(FSHLog.java:1222)
at
org.apache.hadoop.hbase.regionserver.HRegion.doMiniBatchMutation(HRegion.java:3188)
at
org.apache.hadoop.hbase.regionserver.HRegion.batchMutate(HRegion.java:2879)
at
org.apache.hadoop.hbase.regionserver.HRegion.batchMutate(HRegion.java:2819)
at
org.apache.hadoop.hbase.regionserver.RSRpcServices.doBatchOp(RSRpcServices.java:736)
at
org.apache.hadoop.hbase.regionserver.RSRpcServices.doNonAtomicRegionMutation(RSRpcServices.java:698)
at
org.apache.hadoop.hbase.regionserver.RSRpcServices.multi(RSRpcServices.java:2095)
at
org.apache.hadoop.hbase.protobuf.generated.ClientProtos$ClientService$2.callBlockingMethod(ClientProtos.java:32213)
at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:774)
at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:102)
at
org.apache.hadoop.hbase.ipc.RpcExecutor.consumerLoop(RpcExecutor.java:133)
at org.apache.hadoop.hbase.ipc.RpcExecutor$1.run(RpcExecutor.java:108)
at java.lang.Thread.run(Thread.java:756)
RingBufferEventHandler thread waiting for safePointReleasedLatch:
"regionserver/hadoop0369.et2.tbsite.net/11.251.152.226:16020.append-pool2-t1"
prio=10 tid=0x00007efd320d0000 nid=0x1777b waiting on condition
[0x00007efd2d2fa000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x00007f01b48d9178> (a
java.util.concurrent.CountDownLatch$Sync)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
at
java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:834)
at
java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:994)
at
java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1303)
at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:236)
at
org.apache.hadoop.hbase.regionserver.wal.FSHLog$SafePointZigZagLatch.safePointAttained(FSHLog.java:1866)
at
org.apache.hadoop.hbase.regionserver.wal.FSHLog$RingBufferEventHandler.attainSafePoint(FSHLog.java:2066)
at
org.apache.hadoop.hbase.regionserver.wal.FSHLog$RingBufferEventHandler.onEvent(FSHLog.java:2029)
at
org.apache.hadoop.hbase.regionserver.wal.FSHLog$RingBufferEventHandler.onEvent(FSHLog.java:1909)
at
com.lmax.disruptor.BatchEventProcessor.run(BatchEventProcessor.java:128)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:756)
{noformat}
{{FSHLog#replaceWriter}} will call {{SafePointZigZagLatch#releaseSafePoint}} to
count down {{safePointReleasedLatch}}, but replaceWriter got stuck when trying
to publish a sync onto ring buffer:
{noformat}
"regionserver/hadoop0369.et2.tbsite.net/11.251.152.226:16020.logRoller" daemon
prio=10 tid=0x00007efd320c8800 nid=0x16123 runnable [0x00007efd311f6000]
java.lang.Thread.State: TIMED_WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
at
java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:349)
at
com.lmax.disruptor.MultiProducerSequencer.next(MultiProducerSequencer.java:136)
at
com.lmax.disruptor.MultiProducerSequencer.next(MultiProducerSequencer.java:105)
at com.lmax.disruptor.RingBuffer.next(RingBuffer.java:246)
at
org.apache.hadoop.hbase.regionserver.wal.FSHLog.publishSyncOnRingBuffer(FSHLog.java:1481)
at
org.apache.hadoop.hbase.regionserver.wal.FSHLog.publishSyncOnRingBuffer(FSHLog.java:1477)
at
org.apache.hadoop.hbase.regionserver.wal.FSHLog.replaceWriter(FSHLog.java:957)
at
org.apache.hadoop.hbase.regionserver.wal.FSHLog.rollWriter(FSHLog.java:726)
at
org.apache.hadoop.hbase.regionserver.LogRoller.run(LogRoller.java:148)
at java.lang.Thread.run(Thread.java:756)
{noformat}
Thus deadlock happens.
A brief process of how deadlock forms:
{noformat}
ring buffer filled with appends
-> rollWriter happens
-> the only consumer of ring buffer waiting for safePointReleasedLatch
-> rollWriter cannot publish sync since ring buffer is full
-> rollWriter won't release safePointReleasedLatch
{noformat}
This JIRA targeting at resolve this issue, and will add a UT to cover the case
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