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https://issues.apache.org/jira/browse/CASSANDRA-14908?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16704108#comment-16704108
]
wu taiyin commented on CASSANDRA-14908:
---------------------------------------
Yes, i have studied the function getNextBackgroundTask. It will never return
unless it can't mark compacting candidate sstables successfully.
public Collection<AbstractCompactionTask> getMaximalTask(int gcBefore)
{
while (true)
{
//other code
{color:#FF0000}//it will loop infinite if markCompacting always return
false.{color}
if (cfs.getDataTracker().markCompacting(candidate.sstables))
{
LeveledCompactionTask newTask = new LeveledCompactionTask(cfs,
candidate.sstables, candidate.level, gcBefore, candidate.maxSSTableBytes);
newTask.setCompactionType(op);
return Arrays.<AbstractCompactionTask>asList(newTask);
}
}
}
And the doubt of the function "markCompacting" as follows:
public boolean markCompacting(Collection<SSTableReader> sstables, boolean
newTables, boolean offline)
{
assert sstables != null && !Iterables.isEmpty(sstables);
while (true)
{
final View currentView = view.get();
if (Iterables.any(sstables, Predicates.in(currentView.compacting)))
return false;
Predicate live = new Predicate<SSTableReader>()
{
public boolean apply(SSTableReader sstable)
{
{color:#FF0000} *//If the sstable instance in sstablesMap is not the one we
are trying to mark as compacting, it will return false, and markCompacting will
return //false,*{color}*{color:#FF0000}and fall into infinite loop
eventually.{color}*
return{color:#FF0000} currentView.sstablesMap.get(sstable) == sstable{color}
&& !sstable.isMarkedCompacted();
}
};
if (newTables)
assert !Iterables.any(sstables, Predicates.in(currentView.sstables));
else if (!offline && !Iterables.all(sstables, live))
return false;
View newView = currentView.markCompacting(sstables);
if (view.compareAndSet(currentView, newView))
{
notifyCompacting(sstables, true);
return true;
}
}
}
> Deadlock occurs when executing a file selection in levelcompact
> ---------------------------------------------------------------
>
> Key: CASSANDRA-14908
> URL: https://issues.apache.org/jira/browse/CASSANDRA-14908
> Project: Cassandra
> Issue Type: Bug
> Components: Compaction
> Environment: version : cassandra 2.1.15
> jdk: 8
> os:suse
> Reporter: wu taiyin
> Priority: Major
> Attachments: stack.zip
>
>
> detailed exception stack as follows:
> "CompactionExecutor:33616" #142049 daemon prio=1 os_prio=4
> tid=0x00007f73244cc000 nid=0x1919a waiting for monitor entry
> [0x00007fa94e13b000]
> java.lang.Thread.State: {color:#FF0000}BLOCKED{color} (on object monitor)
> at
> org.apache.cassandra.db.compaction.WrappingCompactionStrategy.handleNotification(WrappingCompactionStrategy.java:265)
> - waiting to lock <0x00007faa776209b0> (a
> org.apache.cassandra.db.compaction.WrappingCompactionStrategy)
> at
> org.apache.cassandra.db.DataTracker.notifySSTablesChanged(DataTracker.java:517)
> at org.apache.cassandra.db.DataTracker.replaceReaders(DataTracker.java:408)
> at
> org.apache.cassandra.db.DataTracker.replaceWithNewInstances(DataTracker.java:305)
> at
> org.apache.cassandra.io.sstable.SSTableRewriter.moveStarts(SSTableRewriter.java:337)
> at
> org.apache.cassandra.io.sstable.SSTableRewriter.maybeReopenEarly(SSTableRewriter.java:187)
> at
> org.apache.cassandra.io.sstable.SSTableRewriter.append(SSTableRewriter.java:126)
> at
> org.apache.cassandra.db.compaction.CompactionTask.runMayThrow(CompactionTask.java:197)
> at org.apache.cassandra.utils.WrappedRunnable.run(WrappedRunnable.java:28)
> at
> org.apache.cassandra.db.compaction.CompactionTask.executeInternal(CompactionTask.java:73)
> at
> org.apache.cassandra.db.compaction.AbstractCompactionTask.execute(AbstractCompactionTask.java:59)
> at
> org.apache.cassandra.db.compaction.CompactionManager$BackgroundCompactionCandidate.run(CompactionManager.java:264)
> at java.util.concurrent.Executors$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$Worker.run(ThreadPoolExecutor.java:617)
> at java.lang.Thread.run(Thread.java:745)
> "CompactionExecutor:33615" #142048 daemon prio=1 os_prio=4
> tid=0x00007f7324451800 nid=0x19199 runnable [0x00007fa7a096f000]
> java.lang.Thread.State: RUNNABLE
> at java.util.HashMap.hash(HashMap.java:338)
> at java.util.HashMap.put(HashMap.java:611)
> at java.util.HashSet.add(HashSet.java:219)
> at java.util.AbstractCollection.addAll(AbstractCollection.java:344)
> at java.util.HashSet.<init>(HashSet.java:119)
> at com.google.common.collect.Sets.newHashSet(Sets.java:218)
> at
> {color:#FF0000}org.apache.cassandra.db.compaction.LeveledManifest.getCompactionCandidates(LeveledManifest.java:307){color}
> {color:#FF0000} - locked <0x00007faa77620e70> (a
> org.apache.cassandra.db.compaction.LeveledManifest){color}
> {color:#FF0000} at{color}
> org.apache.cassandra.db.compaction.LeveledCompactionStrategy.getMaximalTask(LeveledCompactionStrategy.java:101)
> at
> org.apache.cassandra.db.compaction.LeveledCompactionStrategy.getNextBackgroundTask(LeveledCompactionStrategy.java:90)
> - locked <0x00007faa77620e30> (a
> org.apache.cassandra.db.compaction.LeveledCompactionStrategy)
> at
> org.apache.cassandra.db.compaction.WrappingCompactionStrategy.getNextBackgroundTask(WrappingCompactionStrategy.java:84)
> - locked <0x00007faa776209b0> (a
> org.apache.cassandra.db.compaction.WrappingCompactionStrategy)
> at
> org.apache.cassandra.db.compaction.CompactionManager$BackgroundCompactionCandidate.run(CompactionManager.java:258)
> 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 java.lang.Thread.run(Thread.java:745)
> "MemtableFlushWriter:22715" #142123 daemon prio=5 os_prio=0
> tid=0x00007f5a3d4ba000 nid=0x24063 waiting for monitor entry
> [0x00007fa8337bd000]
> java.lang.Thread.State: BLOCKED (on object monitor)
> at
> org.apache.cassandra.db.compaction.WrappingCompactionStrategy.handleNotification(WrappingCompactionStrategy.java:265)
> - waiting to lock <0x00007faa776209b0> (a
> org.apache.cassandra.db.compaction.WrappingCompactionStrategy)
> at org.apache.cassandra.db.DataTracker.notifyAdded(DataTracker.java:531)
> at org.apache.cassandra.db.DataTracker.replaceFlushed(DataTracker.java:179)
> at
> org.apache.cassandra.db.compaction.AbstractCompactionStrategy.replaceFlushed(AbstractCompactionStrategy.java:234)
> at
> org.apache.cassandra.db.ColumnFamilyStore.replaceFlushed(ColumnFamilyStore.java:1521)
> at
> org.apache.cassandra.db.Memtable$FlushRunnable.runMayThrow(Memtable.java:336)
> at org.apache.cassandra.utils.WrappedRunnable.run(WrappedRunnable.java:28)
> at
> com.google.common.util.concurrent.MoreExecutors$SameThreadExecutorService.execute(MoreExecutors.java:297)
> at
> org.apache.cassandra.db.ColumnFamilyStore$Flush.run(ColumnFamilyStore.java:1127)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> at java.lang.Thread.run(Thread.java:745)
> "MemtableFlushWriter:22711" #142116 daemon prio=5 os_prio=0
> tid=0x00007f5a3d338000 nid=0x21ccf waiting for monitor entry
> [0x00007fa94e084000]
> java.lang.Thread.State: BLOCKED (on object monitor)
> at
> org.apache.cassandra.db.compaction.WrappingCompactionStrategy.handleNotification(WrappingCompactionStrategy.java:265)
> - waiting to lock <0x00007faa776209b0> (a
> org.apache.cassandra.db.compaction.WrappingCompactionStrategy)
> at org.apache.cassandra.db.DataTracker.notifyAdded(DataTracker.java:531)
> at org.apache.cassandra.db.DataTracker.replaceFlushed(DataTracker.java:179)
> at
> org.apache.cassandra.db.compaction.AbstractCompactionStrategy.replaceFlushed(AbstractCompactionStrategy.java:234)
> at
> org.apache.cassandra.db.ColumnFamilyStore.replaceFlushed(ColumnFamilyStore.java:1521)
> at
> org.apache.cassandra.db.Memtable$FlushRunnable.runMayThrow(Memtable.java:336)
> at org.apache.cassandra.utils.WrappedRunnable.run(WrappedRunnable.java:28)
> at
> com.google.common.util.concurrent.MoreExecutors$SameThreadExecutorService.execute(MoreExecutors.java:297)
> at
> org.apache.cassandra.db.ColumnFamilyStore$Flush.run(ColumnFamilyStore.java:1127)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> at java.lang.Thread.run(Thread.java:745)
>
>
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