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Posted to commits@cassandra.apache.org by "Jaydeepkumar Chovatia (JIRA)" <ji...@apache.org> on 2017/06/09 23:06:18 UTC

[jira] [Created] (CASSANDRA-13587) Deadlock during CommitLog replay when Cassandra restart

Jaydeepkumar Chovatia created CASSANDRA-13587:
-------------------------------------------------

             Summary: Deadlock during CommitLog replay when Cassandra restart
                 Key: CASSANDRA-13587
                 URL: https://issues.apache.org/jira/browse/CASSANDRA-13587
             Project: Cassandra
          Issue Type: Bug
          Components: Core
            Reporter: Jaydeepkumar Chovatia
             Fix For: 3.0.14


Possible deadlock found when Cassandra is replaying commit log and at the same time Mutation gets triggered by SSTableReader(SystemKeyspace.persistSSTableReadMeter). As a result Cassandra restart hangs forever

Please find details of stack trace here:

*Frame#1* This thread is trying to apply {{persistSSTableReadMeter}} mutation and as a result it has called {{writeOrder.start()}} in {{Keyspace.java:533}}
but there are no Commitlog Segments available because {{createReserveSegments (CommitLogSegmentManager.java)}} is not yet {{true}} 

Hence this thread is blocked on {{createReserveSegments}} to become {{true}}, please note this thread has already started {{writeOrder}}

{{"pool-11-thread-1" #251 prio=5 os_prio=0 tid=0x00007fe128478400 nid=0x1b274 waiting on condition [0x00007fe1389a0000]
   java.lang.Thread.State: WAITING (parking)
        at sun.misc.Unsafe.park(Native Method)
        at java.util.concurrent.locks.LockSupport.park(LockSupport.java:304)
        at org.apache.cassandra.utils.concurrent.WaitQueue$AbstractSignal.awaitUninterruptibly(WaitQueue.java:279)
        at org.apache.cassandra.db.commitlog.CommitLogSegmentManager.advanceAllocatingFrom(CommitLogSegmentManager.java:277)
        at org.apache.cassandra.db.commitlog.CommitLogSegmentManager.allocate(CommitLogSegmentManager.java:196)
        at org.apache.cassandra.db.commitlog.CommitLog.add(CommitLog.java:260)
        at org.apache.cassandra.db.Keyspace.applyInternal(Keyspace.java:540)
        at org.apache.cassandra.db.Keyspace.apply(Keyspace.java:421)
        at org.apache.cassandra.db.Mutation.apply(Mutation.java:210)
        at org.apache.cassandra.db.Mutation.apply(Mutation.java:215)
        at org.apache.cassandra.db.Mutation.apply(Mutation.java:224)
        at org.apache.cassandra.cql3.statements.ModificationStatement.executeInternalWithoutCondition(ModificationStatement.java:566)
        at org.apache.cassandra.cql3.statements.ModificationStatement.executeInternal(ModificationStatement.java:556)
        at org.apache.cassandra.cql3.QueryProcessor.executeInternal(QueryProcessor.java:295)
        at org.apache.cassandra.db.SystemKeyspace.persistSSTableReadMeter(SystemKeyspace.java:1181)
        at org.apache.cassandra.io.sstable.format.SSTableReader$GlobalTidy$1.run(SSTableReader.java:2202)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)
}}

*Frame#2* This thread is trying to recover commit logs and as a result it tries to flush Memtable by calling following code:
{{futures.add(Keyspace.open(SystemKeyspace.NAME).getColumnFamilyStore(SystemKeyspace.BATCHES).forceFlush());}}
As a result Frame#3 (below) gets created

{{"main" #1 prio=5 os_prio=0 tid=0x00007fe1c64ec400 nid=0x1af29 waiting on condition [0x00007fe1c94a1000]
   java.lang.Thread.State: WAITING (parking)
        at sun.misc.Unsafe.park(Native Method)
        - parking to wait for  <0x00000006370da0c0> (a com.google.common.util.concurrent.ListenableFutureTask)
        at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
        at java.util.concurrent.FutureTask.awaitDone(FutureTask.java:429)
        at java.util.concurrent.FutureTask.get(FutureTask.java:191)
        at org.apache.cassandra.utils.FBUtilities.waitOnFutures(FBUtilities.java:383)
        at org.apache.cassandra.db.commitlog.CommitLogReplayer.blockForWrites(CommitLogReplayer.java:207)
        at org.apache.cassandra.db.commitlog.CommitLog.recover(CommitLog.java:182)
        at org.apache.cassandra.db.commitlog.CommitLog.recover(CommitLog.java:161)
        at org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:295)
        at org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:569)
        at org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:697)
}}

*Frame#3* This thread is waiting at {{writeBarrier.await();}} in {{ColumnFamilyStore.java:1027}} 
but {{writeBarrier}} is locked by thread in Frame#1, and Frame#1 thread is waiting for more CommitlogSegements to be available. 
Frame#1 thread will not get new segment because variable {{createReserveSegments(CommitLogSegmentManager.java)}} is not yet {{true}}. 
This variable gets set to {{true}} after successful execution of Frame#2.

Here we can see Frame#{2+3} and Frame#1 are in deadlock state and Cassandra restart hangs forever.
 
{{
"MemtableFlushWriter:5" #433 daemon prio=5 os_prio=0 tid=0x00007e7a4b8b0400 nid=0x1dea8 waiting on condition [0x00007e753c2ca000]
   java.lang.Thread.State: WAITING (parking)
        at sun.misc.Unsafe.park(Native Method)
        at java.util.concurrent.locks.LockSupport.park(LockSupport.java:304)
        at org.apache.cassandra.utils.concurrent.WaitQueue$AbstractSignal.awaitUninterruptibly(WaitQueue.java:279)
        at org.apache.cassandra.utils.concurrent.OpOrder$Barrier.await(OpOrder.java:419)
        at org.apache.cassandra.db.ColumnFamilyStore$Flush.run(ColumnFamilyStore.java:1027)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at org.apache.cassandra.concurrent.NamedThreadFactory.lambda$threadLocalDeallocator$0(NamedThreadFactory.java:79)
        at org.apache.cassandra.concurrent.NamedThreadFactory$$Lambda$4/1527007086.run(Unknown Source)
        at java.lang.Thread.run(Thread.java:745)

"MemtablePostFlush:3" #432 daemon prio=5 os_prio=0 tid=0x00007e7a4b8b0000 nid=0x1dea7 waiting on condition [0x00007e753c30b000]
   java.lang.Thread.State: WAITING (parking)
        at sun.misc.Unsafe.park(Native Method)
        - parking to wait for  <0x00000006370d9cd0> (a java.util.concurrent.CountDownLatch$Sync)
        at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:997)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1304)
        at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:231)
        at org.apache.cassandra.db.ColumnFamilyStore$PostFlush.call(ColumnFamilyStore.java:941)
        at org.apache.cassandra.db.ColumnFamilyStore$PostFlush.call(ColumnFamilyStore.java:924)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at org.apache.cassandra.concurrent.NamedThreadFactory.lambda$threadLocalDeallocator$0(NamedThreadFactory.java:79)
        at org.apache.cassandra.concurrent.NamedThreadFactory$$Lambda$4/1527007086.run(Unknown Source)
        at java.lang.Thread.run(Thread.java:745)
}}



*Solution*: I am proposing that we should enable variable {{createReserveSegments(CommitLogSegmentManager.java)}} before recovering any CommitLogs in CommitLog.java file
so this will not block Frame#1 from acquiring new segment as a result Frame#1 will finish and then Frame#2 will also finish, please let me know your opinion.




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