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https://issues.apache.org/jira/browse/CASSANDRA-4799?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13476329#comment-13476329
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Yuki Morishita commented on CASSANDRA-4799:
-------------------------------------------
I found two problems here.
1) Test does not completely setup necessary SSTables and causes above
AssertionError.
LCS test uses CFS#forceFlush to generate enough SSTables at the beginning of
the test, but since the method is asynchronous call, there is a chance that
test proceeds without sufficient SSTables to fill up L2 and causes AE at
strat.getLevelSize(2) > 0.
Fix for this is to change forceFlush to forceBlockingFlush.
(diff:
https://github.com/yukim/cassandra/commit/0d16efc6d7592e61f15598d5a4e3cc81d2760007)
2) Repair sometimes causes AssertionError with LCS
During the test, I encountered below error several times.
{code}
ERROR [ValidationExecutor:1] 2012-10-12 14:39:18,660 SchemaLoader.java (line
73) Fatal exception in thread Thread[ValidationExecutor:1,1,main]
java.lang.AssertionError
at
org.apache.cassandra.db.compaction.LeveledCompactionStrategy.getScanners(LeveledCompactionStrategy.java:183)
at
org.apache.cassandra.db.compaction.CompactionManager$ValidationCompactionIterable.<init>(CompactionManager.java:879)
at
org.apache.cassandra.db.compaction.CompactionManager.doValidationCompaction(CompactionManager.java:743)
at
org.apache.cassandra.db.compaction.CompactionManager.access$700(CompactionManager.java:71)
at
org.apache.cassandra.db.compaction.CompactionManager$7.call(CompactionManager.java:481)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
{code}
AssertionError comes from following assert code in LCS#getScanners:
{code}
for (SSTableReader sstable : sstables)
{
int level = manifest.levelOf(sstable);
assert level >= 0;
byLevel.get(level).add(sstable);
}
{code}
LeveledManifest#levelOf method returns level of SSTable or -1 if SSTable is not
yet added to LeveledManifest. Here, each SSTable comes from CF's DataTracker.
Every time SSTable is written by flush/compaction, it gets added to DataTracker
and after that, added to LeveledManifest if you are using LCS.
If above repair code is executed between those two, you will get AssertionError.
My proposed fix is to remove assertion and treat SSTables that do not belong
LeveledManifest yet as L0 SSTables.
(diff:
https://github.com/yukim/cassandra/commit/c8a0fb9a9128e47ec3d07926eb26f6fd93664f52)
Problem (2) also exists in 1.1 branch, but without assertion. We may want to
fix this in 1.1 too.
> assertion failure in leveled compaction test
> --------------------------------------------
>
> Key: CASSANDRA-4799
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4799
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Reporter: Brandon Williams
> Assignee: Yuki Morishita
> Fix For: 1.2.0
>
>
> It's somewhat rare, but I'm regularly seeing this failure on trunk:
> {noformat}
> [junit] Testcase:
> testValidationMultipleSSTablePerLevel(org.apache.cassandra.db.compaction.LeveledCompactionStrategyTest):
> FAILED
> [junit] null
> [junit] junit.framework.AssertionFailedError
> [junit] at
> org.apache.cassandra.db.compaction.LeveledCompactionStrategyTest.testValidationMultipleSSTablePerLevel(LeveledCompactionStrategyTest.java:78)
> [junit]
> [junit]
> [junit] Test
> org.apache.cassandra.db.compaction.LeveledCompactionStrategyTest FAILED
> {noformat}
> I suspect there's a deeper problem, since this is a pretty fundamental
> assertion.
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