[jira] [Commented] (CASSANDRA-6596) Split out outgoing stream throughput within a DC and inter-DC

2014-06-26 Thread Thomas Vachon (JIRA)

[ 
https://issues.apache.org/jira/browse/CASSANDRA-6596?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=14044558#comment-14044558
 ] 

Thomas Vachon commented on CASSANDRA-6596:
--

I second this. It's a huge win for us but we can't go to 2.1 yet



 Split out outgoing stream throughput within a DC and inter-DC
 -

 Key: CASSANDRA-6596
 URL: https://issues.apache.org/jira/browse/CASSANDRA-6596
 Project: Cassandra
  Issue Type: Improvement
  Components: Core
Reporter: Jeremy Hanna
Assignee: Vijay
Priority: Minor
 Fix For: 2.1 beta1

 Attachments: 0001-CASSANDRA-6596.patch


 Currently the outgoing stream throughput setting doesn't differentiate 
 between when it goes to another node in the same DC and when it goes to 
 another DC across a potentially bandwidth limited link.  It would be nice to 
 have that split out so that it could be tuned for each type of link.



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[jira] [Commented] (CASSANDRA-4492) HintsColumnFamily compactions hang when using multithreaded compaction

2012-12-18 Thread Thomas Vachon (JIRA)

[ 
https://issues.apache.org/jira/browse/CASSANDRA-4492?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13534973#comment-13534973
 ] 

Thomas Vachon commented on CASSANDRA-4492:
--

{quote}Looking at the code it seems there are two places where 
HintedHandoffManager calls a user defined compact() for all sstable{quote}

Well that would explain why everytime I start and I get hints, I get every 
sstable compacted

 HintsColumnFamily compactions hang when using multithreaded compaction
 --

 Key: CASSANDRA-4492
 URL: https://issues.apache.org/jira/browse/CASSANDRA-4492
 Project: Cassandra
  Issue Type: Bug
Affects Versions: 1.0.11
Reporter: Jason Harvey
Priority: Minor
 Attachments: jstack.txt


 Running into an issue on a 6 node ring running 1.0.11 where HintsColumnFamily 
 compactions often hang indefinitely when using multithreaded compaction. 
 Nothing of note in the logs. In some cases, the compaction hangs before a tmp 
 sstable is even created.
 I've wiped out every hints sstable and restarted several times. The issue 
 always comes back rather quickly and predictably. The compactions sometimes 
 complete if the hint sstables are very small. Disabling multithreaded 
 compaction stops this issue from occurring.
 Compactions of all other CFs seem to work just fine.
 This ring was upgraded from 1.0.7. I didn't keep any hints from the upgrade.
 I should note that the ring gets a huge amount of writes, and as a result the 
 HintedHandoff rows get be quite wide. I didn't see any large-row compaction 
 notices when the compaction was hanging (perhaps the bug was triggered by 
 incremental compaction?). After disabling multithreaded compaction, several 
 of the rows that were successfully compacted were over 1GB.
 Here is the output I see from compactionstats where a compaction has hung. 
 The 'bytes compacted' column never changes.
 {code}
 pending tasks: 1
   compaction typekeyspace   column family bytes compacted 
 bytes total  progress
Compaction  systemHintsColumnFamily  268082
464784758 0.06%
 {code}
 The hung thread stack is as follows: (full jstack attached, as well)
 {code}
 CompactionExecutor:37 daemon prio=10 tid=0x063df800 nid=0x49d9 
 waiting on condition [0x7eb8c6ffa000]
java.lang.Thread.State: WAITING (parking)
 at sun.misc.Unsafe.park(Native Method)
 - parking to wait for  0x00050f2e0e58 (a 
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
 at java.util.concurrent.locks.LockSupport.park(LockSupport.java:158)
 at 
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1987)
 at 
 java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:399)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Deserializer.computeNext(ParallelCompactionIterable.java:329)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Deserializer.computeNext(ParallelCompactionIterable.java:281)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 org.apache.cassandra.utils.MergeIterator$Candidate.advance(MergeIterator.java:147)
 at 
 org.apache.cassandra.utils.MergeIterator$ManyToOne.advance(MergeIterator.java:126)
 at 
 org.apache.cassandra.utils.MergeIterator$ManyToOne.computeNext(MergeIterator.java:100)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Unwrapper.computeNext(ParallelCompactionIterable.java:101)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Unwrapper.computeNext(ParallelCompactionIterable.java:88)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 com.google.common.collect.Iterators$7.computeNext(Iterators.java:614)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 org.apache.cassandra.db.compaction.CompactionTask.execute(CompactionTask.java:141)
 at 
 org.apache.cassandra.db.compaction.CompactionManager$7.call(CompactionManager.java:395)
 at 

[jira] [Comment Edited] (CASSANDRA-4492) HintsColumnFamily compactions hang when using multithreaded compaction

2012-12-18 Thread Thomas Vachon (JIRA)

[ 
https://issues.apache.org/jira/browse/CASSANDRA-4492?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13534973#comment-13534973
 ] 

Thomas Vachon edited comment on CASSANDRA-4492 at 12/18/12 3:35 PM:


{quote}Looking at the code it seems there are two places where 
HintedHandoffManager calls a user defined compact() for all sstable{quote}

Well that would explain why everytime I restart and I get hints, I get every 
sstable compacted

  was (Author: tvachon):
{quote}Looking at the code it seems there are two places where 
HintedHandoffManager calls a user defined compact() for all sstable{quote}

Well that would explain why everytime I start and I get hints, I get every 
sstable compacted
  
 HintsColumnFamily compactions hang when using multithreaded compaction
 --

 Key: CASSANDRA-4492
 URL: https://issues.apache.org/jira/browse/CASSANDRA-4492
 Project: Cassandra
  Issue Type: Bug
Affects Versions: 1.0.11
Reporter: Jason Harvey
Priority: Minor
 Attachments: jstack.txt


 Running into an issue on a 6 node ring running 1.0.11 where HintsColumnFamily 
 compactions often hang indefinitely when using multithreaded compaction. 
 Nothing of note in the logs. In some cases, the compaction hangs before a tmp 
 sstable is even created.
 I've wiped out every hints sstable and restarted several times. The issue 
 always comes back rather quickly and predictably. The compactions sometimes 
 complete if the hint sstables are very small. Disabling multithreaded 
 compaction stops this issue from occurring.
 Compactions of all other CFs seem to work just fine.
 This ring was upgraded from 1.0.7. I didn't keep any hints from the upgrade.
 I should note that the ring gets a huge amount of writes, and as a result the 
 HintedHandoff rows get be quite wide. I didn't see any large-row compaction 
 notices when the compaction was hanging (perhaps the bug was triggered by 
 incremental compaction?). After disabling multithreaded compaction, several 
 of the rows that were successfully compacted were over 1GB.
 Here is the output I see from compactionstats where a compaction has hung. 
 The 'bytes compacted' column never changes.
 {code}
 pending tasks: 1
   compaction typekeyspace   column family bytes compacted 
 bytes total  progress
Compaction  systemHintsColumnFamily  268082
464784758 0.06%
 {code}
 The hung thread stack is as follows: (full jstack attached, as well)
 {code}
 CompactionExecutor:37 daemon prio=10 tid=0x063df800 nid=0x49d9 
 waiting on condition [0x7eb8c6ffa000]
java.lang.Thread.State: WAITING (parking)
 at sun.misc.Unsafe.park(Native Method)
 - parking to wait for  0x00050f2e0e58 (a 
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
 at java.util.concurrent.locks.LockSupport.park(LockSupport.java:158)
 at 
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1987)
 at 
 java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:399)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Deserializer.computeNext(ParallelCompactionIterable.java:329)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Deserializer.computeNext(ParallelCompactionIterable.java:281)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 org.apache.cassandra.utils.MergeIterator$Candidate.advance(MergeIterator.java:147)
 at 
 org.apache.cassandra.utils.MergeIterator$ManyToOne.advance(MergeIterator.java:126)
 at 
 org.apache.cassandra.utils.MergeIterator$ManyToOne.computeNext(MergeIterator.java:100)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Unwrapper.computeNext(ParallelCompactionIterable.java:101)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Unwrapper.computeNext(ParallelCompactionIterable.java:88)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 com.google.common.collect.Iterators$7.computeNext(Iterators.java:614)
 at 
 

[jira] [Commented] (CASSANDRA-4492) HintsColumnFamily compactions hang when using multithreaded compaction

2012-12-11 Thread Thomas Vachon (JIRA)

[ 
https://issues.apache.org/jira/browse/CASSANDRA-4492?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13529251#comment-13529251
 ] 

Thomas Vachon commented on CASSANDRA-4492:
--

[~jbellis] no I can't.  We turned off MT compaction and they have been 
compacted away.

 HintsColumnFamily compactions hang when using multithreaded compaction
 --

 Key: CASSANDRA-4492
 URL: https://issues.apache.org/jira/browse/CASSANDRA-4492
 Project: Cassandra
  Issue Type: Bug
Affects Versions: 1.0.11
Reporter: Jason Harvey
Priority: Minor
 Attachments: jstack.txt


 Running into an issue on a 6 node ring running 1.0.11 where HintsColumnFamily 
 compactions often hang indefinitely when using multithreaded compaction. 
 Nothing of note in the logs. In some cases, the compaction hangs before a tmp 
 sstable is even created.
 I've wiped out every hints sstable and restarted several times. The issue 
 always comes back rather quickly and predictably. The compactions sometimes 
 complete if the hint sstables are very small. Disabling multithreaded 
 compaction stops this issue from occurring.
 Compactions of all other CFs seem to work just fine.
 This ring was upgraded from 1.0.7. I didn't keep any hints from the upgrade.
 I should note that the ring gets a huge amount of writes, and as a result the 
 HintedHandoff rows get be quite wide. I didn't see any large-row compaction 
 notices when the compaction was hanging (perhaps the bug was triggered by 
 incremental compaction?). After disabling multithreaded compaction, several 
 of the rows that were successfully compacted were over 1GB.
 Here is the output I see from compactionstats where a compaction has hung. 
 The 'bytes compacted' column never changes.
 {code}
 pending tasks: 1
   compaction typekeyspace   column family bytes compacted 
 bytes total  progress
Compaction  systemHintsColumnFamily  268082
464784758 0.06%
 {code}
 The hung thread stack is as follows: (full jstack attached, as well)
 {code}
 CompactionExecutor:37 daemon prio=10 tid=0x063df800 nid=0x49d9 
 waiting on condition [0x7eb8c6ffa000]
java.lang.Thread.State: WAITING (parking)
 at sun.misc.Unsafe.park(Native Method)
 - parking to wait for  0x00050f2e0e58 (a 
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
 at java.util.concurrent.locks.LockSupport.park(LockSupport.java:158)
 at 
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1987)
 at 
 java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:399)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Deserializer.computeNext(ParallelCompactionIterable.java:329)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Deserializer.computeNext(ParallelCompactionIterable.java:281)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 org.apache.cassandra.utils.MergeIterator$Candidate.advance(MergeIterator.java:147)
 at 
 org.apache.cassandra.utils.MergeIterator$ManyToOne.advance(MergeIterator.java:126)
 at 
 org.apache.cassandra.utils.MergeIterator$ManyToOne.computeNext(MergeIterator.java:100)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Unwrapper.computeNext(ParallelCompactionIterable.java:101)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Unwrapper.computeNext(ParallelCompactionIterable.java:88)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 com.google.common.collect.Iterators$7.computeNext(Iterators.java:614)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 org.apache.cassandra.db.compaction.CompactionTask.execute(CompactionTask.java:141)
 at 
 org.apache.cassandra.db.compaction.CompactionManager$7.call(CompactionManager.java:395)
 at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
 at java.util.concurrent.FutureTask.run(FutureTask.java:138)
 at 
 

[jira] [Commented] (CASSANDRA-4492) HintsColumnFamily compactions hang when using multithreaded compaction

2012-12-11 Thread Thomas Vachon (JIRA)

[ 
https://issues.apache.org/jira/browse/CASSANDRA-4492?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13529284#comment-13529284
 ] 

Thomas Vachon commented on CASSANDRA-4492:
--

No, update heavy though 

 HintsColumnFamily compactions hang when using multithreaded compaction
 --

 Key: CASSANDRA-4492
 URL: https://issues.apache.org/jira/browse/CASSANDRA-4492
 Project: Cassandra
  Issue Type: Bug
Affects Versions: 1.0.11
Reporter: Jason Harvey
Priority: Minor
 Attachments: jstack.txt


 Running into an issue on a 6 node ring running 1.0.11 where HintsColumnFamily 
 compactions often hang indefinitely when using multithreaded compaction. 
 Nothing of note in the logs. In some cases, the compaction hangs before a tmp 
 sstable is even created.
 I've wiped out every hints sstable and restarted several times. The issue 
 always comes back rather quickly and predictably. The compactions sometimes 
 complete if the hint sstables are very small. Disabling multithreaded 
 compaction stops this issue from occurring.
 Compactions of all other CFs seem to work just fine.
 This ring was upgraded from 1.0.7. I didn't keep any hints from the upgrade.
 I should note that the ring gets a huge amount of writes, and as a result the 
 HintedHandoff rows get be quite wide. I didn't see any large-row compaction 
 notices when the compaction was hanging (perhaps the bug was triggered by 
 incremental compaction?). After disabling multithreaded compaction, several 
 of the rows that were successfully compacted were over 1GB.
 Here is the output I see from compactionstats where a compaction has hung. 
 The 'bytes compacted' column never changes.
 {code}
 pending tasks: 1
   compaction typekeyspace   column family bytes compacted 
 bytes total  progress
Compaction  systemHintsColumnFamily  268082
464784758 0.06%
 {code}
 The hung thread stack is as follows: (full jstack attached, as well)
 {code}
 CompactionExecutor:37 daemon prio=10 tid=0x063df800 nid=0x49d9 
 waiting on condition [0x7eb8c6ffa000]
java.lang.Thread.State: WAITING (parking)
 at sun.misc.Unsafe.park(Native Method)
 - parking to wait for  0x00050f2e0e58 (a 
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
 at java.util.concurrent.locks.LockSupport.park(LockSupport.java:158)
 at 
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1987)
 at 
 java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:399)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Deserializer.computeNext(ParallelCompactionIterable.java:329)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Deserializer.computeNext(ParallelCompactionIterable.java:281)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 org.apache.cassandra.utils.MergeIterator$Candidate.advance(MergeIterator.java:147)
 at 
 org.apache.cassandra.utils.MergeIterator$ManyToOne.advance(MergeIterator.java:126)
 at 
 org.apache.cassandra.utils.MergeIterator$ManyToOne.computeNext(MergeIterator.java:100)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Unwrapper.computeNext(ParallelCompactionIterable.java:101)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Unwrapper.computeNext(ParallelCompactionIterable.java:88)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 com.google.common.collect.Iterators$7.computeNext(Iterators.java:614)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 org.apache.cassandra.db.compaction.CompactionTask.execute(CompactionTask.java:141)
 at 
 org.apache.cassandra.db.compaction.CompactionManager$7.call(CompactionManager.java:395)
 at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
 at java.util.concurrent.FutureTask.run(FutureTask.java:138)
 at 
 

[jira] [Commented] (CASSANDRA-4492) HintsColumnFamily compactions hang when using multithreaded compaction

2012-11-29 Thread Thomas Vachon (JIRA)

[ 
https://issues.apache.org/jira/browse/CASSANDRA-4492?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13506806#comment-13506806
 ] 

Thomas Vachon commented on CASSANDRA-4492:
--

This actually is severe.  Since they hang, it blocks all schema changes.

 HintsColumnFamily compactions hang when using multithreaded compaction
 --

 Key: CASSANDRA-4492
 URL: https://issues.apache.org/jira/browse/CASSANDRA-4492
 Project: Cassandra
  Issue Type: Bug
Affects Versions: 1.0.11
Reporter: Jason Harvey
Priority: Minor
 Attachments: jstack.txt


 Running into an issue on a 6 node ring running 1.0.11 where HintsColumnFamily 
 compactions often hang indefinitely when using multithreaded compaction. 
 Nothing of note in the logs. In some cases, the compaction hangs before a tmp 
 sstable is even created.
 I've wiped out every hints sstable and restarted several times. The issue 
 always comes back rather quickly and predictably. The compactions sometimes 
 complete if the hint sstables are very small. Disabling multithreaded 
 compaction stops this issue from occurring.
 Compactions of all other CFs seem to work just fine.
 This ring was upgraded from 1.0.7. I didn't keep any hints from the upgrade.
 I should note that the ring gets a huge amount of writes, and as a result the 
 HintedHandoff rows get be quite wide. I didn't see any large-row compaction 
 notices when the compaction was hanging (perhaps the bug was triggered by 
 incremental compaction?). After disabling multithreaded compaction, several 
 of the rows that were successfully compacted were over 1GB.
 Here is the output I see from compactionstats where a compaction has hung. 
 The 'bytes compacted' column never changes.
 {code}
 pending tasks: 1
   compaction typekeyspace   column family bytes compacted 
 bytes total  progress
Compaction  systemHintsColumnFamily  268082
464784758 0.06%
 {code}
 The hung thread stack is as follows: (full jstack attached, as well)
 {code}
 CompactionExecutor:37 daemon prio=10 tid=0x063df800 nid=0x49d9 
 waiting on condition [0x7eb8c6ffa000]
java.lang.Thread.State: WAITING (parking)
 at sun.misc.Unsafe.park(Native Method)
 - parking to wait for  0x00050f2e0e58 (a 
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
 at java.util.concurrent.locks.LockSupport.park(LockSupport.java:158)
 at 
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1987)
 at 
 java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:399)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Deserializer.computeNext(ParallelCompactionIterable.java:329)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Deserializer.computeNext(ParallelCompactionIterable.java:281)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 org.apache.cassandra.utils.MergeIterator$Candidate.advance(MergeIterator.java:147)
 at 
 org.apache.cassandra.utils.MergeIterator$ManyToOne.advance(MergeIterator.java:126)
 at 
 org.apache.cassandra.utils.MergeIterator$ManyToOne.computeNext(MergeIterator.java:100)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Unwrapper.computeNext(ParallelCompactionIterable.java:101)
 at 
 org.apache.cassandra.db.compaction.ParallelCompactionIterable$Unwrapper.computeNext(ParallelCompactionIterable.java:88)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 com.google.common.collect.Iterators$7.computeNext(Iterators.java:614)
 at 
 com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:140)
 at 
 com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:135)
 at 
 org.apache.cassandra.db.compaction.CompactionTask.execute(CompactionTask.java:141)
 at 
 org.apache.cassandra.db.compaction.CompactionManager$7.call(CompactionManager.java:395)
 at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
 at java.util.concurrent.FutureTask.run(FutureTask.java:138)
 at