[CASSANDRA-8476] RE in writeSortedContents or replaceFlushed blocks compaction threads indefinitely.

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Duplicate
• Fix Version/s: 2.0.12
• Severity: Normal
• Assignee: Pavel Yaskevich
• Reporter: Pavel Yaskevich

Authors

Pavel Yaskevich

Reviewers

Jason Brown

• Created: 13/Dec/14 00:26
• Updated: 16/Apr/19 09:31
• Resolved: 14/Dec/14 05:52

Description

Encountered this problem while generating some test data, incremental backup failed to create hard-links to some of the of the system files (which is done at the end of each compaction):

Example of the RE stacktrace:

14/12/12 15:47:47 ERROR cassandra.SchemaLoader: Fatal exception in thread Thread[FlushWriter:5,5,main]
java.lang.RuntimeException: Tried to create duplicate hard link to <path>/cassandra/data/system/IndexInfo/backups/system-IndexInfo-jb-1-Index.db
	at org.apache.cassandra.io.util.FileUtils.createHardLink(FileUtils.java:75)
	at org.apache.cassandra.io.sstable.SSTableReader.createLinks(SSTableReader.java:1222)
	at org.apache.cassandra.db.DataTracker.maybeIncrementallyBackup(DataTracker.java:189)
	at org.apache.cassandra.db.DataTracker.replaceFlushed(DataTracker.java:166)
	at org.apache.cassandra.db.compaction.AbstractCompactionStrategy.replaceFlushed(AbstractCompactionStrategy.java:231)
	at org.apache.cassandra.db.ColumnFamilyStore.replaceFlushed(ColumnFamilyStore.java:1141)
	at org.apache.cassandra.db.Memtable$FlushRunnable.runWith(Memtable.java:343)
	at org.apache.cassandra.io.util.DiskAwareRunnable.runMayThrow(DiskAwareRunnable.java:48)
	at org.apache.cassandra.utils.WrappedRunnable.run(WrappedRunnable.java:28)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:744)
14

jstack shows that CompactionExecutor threads are now blocked waiting on the flush future which will actually never decrement a latch.

"CompactionExecutor:125" daemon prio=5 tid=0x00007fb3a10da800 nid=0x13c43 waiting on condition [0x000000012a900000]
   java.lang.Thread.State: WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x000000071b669088> (a java.util.concurrent.FutureTask)
	at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
	at java.util.concurrent.FutureTask.awaitDone(FutureTask.java:425)
	at java.util.concurrent.FutureTask.get(FutureTask.java:187)
	at org.apache.cassandra.utils.FBUtilities.waitOnFuture(FBUtilities.java:409)
	at org.apache.cassandra.db.SystemKeyspace.forceBlockingFlush(SystemKeyspace.java:457)
	at org.apache.cassandra.db.SystemKeyspace.finishCompaction(SystemKeyspace.java:203)
	at org.apache.cassandra.db.compaction.CompactionTask.runWith(CompactionTask.java:225)
	at org.apache.cassandra.io.util.DiskAwareRunnable.runMayThrow(DiskAwareRunnable.java:48)
	at org.apache.cassandra.utils.WrappedRunnable.run(WrappedRunnable.java:28)
	at org.apache.cassandra.db.compaction.CompactionTask.executeInternal(CompactionTask.java:60)
	at org.apache.cassandra.db.compaction.AbstractCompactionTask.execute(AbstractCompactionTask.java:59)
	at org.apache.cassandra.db.compaction.CompactionManager$BackgroundCompactionTask.run(CompactionManager.java:198)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	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:744)

"CompactionExecutor:124" daemon prio=5 tid=0x00007fb35cc09800 nid=0x13a2b waiting on condition [0x000000012934f000]
   java.lang.Thread.State: WAITING (parking)
	at sun.misc.Unsafe.park(Native Method)
	- parking to wait for  <0x00000007ce4bf918> (a java.util.concurrent.FutureTask)
	at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
	at java.util.concurrent.FutureTask.awaitDone(FutureTask.java:425)
	at java.util.concurrent.FutureTask.get(FutureTask.java:187)
	at org.apache.cassandra.utils.FBUtilities.waitOnFuture(FBUtilities.java:409)
	at org.apache.cassandra.db.SystemKeyspace.forceBlockingFlush(SystemKeyspace.java:457)
	at org.apache.cassandra.db.SystemKeyspace.finishCompaction(SystemKeyspace.java:203)
	at org.apache.cassandra.db.compaction.CompactionTask.runWith(CompactionTask.java:225)
	at org.apache.cassandra.io.util.DiskAwareRunnable.runMayThrow(DiskAwareRunnable.java:48)
	at org.apache.cassandra.utils.WrappedRunnable.run(WrappedRunnable.java:28)
	at org.apache.cassandra.db.compaction.CompactionTask.executeInternal(CompactionTask.java:60)
	at org.apache.cassandra.db.compaction.AbstractCompactionTask.execute(AbstractCompactionTask.java:59)
	at org.apache.cassandra.db.compaction.CompactionManager$BackgroundCompactionTask.run(CompactionManager.java:198)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	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:744)

Issue Links

• duplicates: CASSANDRA-7275 Errors in FlushRunnable may leave threads hung