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https://issues.apache.org/jira/browse/CASSANDRA-3306?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13483157#comment-13483157
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Sylvain Lebresne commented on CASSANDRA-3306:
---------------------------------------------
Good analysis Yuki. I'm not really sure what is the right fix though. Given
that this should very rarely happen (repair uses a much higher failure
detection threshold than the normal one, though maybe we can increase it even
more to make this even less likely) and that I don't seen any obvious way to
avoid that kind of situation, maybe making DataTracker handle duplicate
addition of a SSTableReader is the simplest thing to do. The obvious way to do
that would be to change the View sstables List to a Set, which leads me to the
current commentary in the code:
{noformat}
// We can't use a SortedSet here because "the ordering maintained by a
sorted set (whether or not an
// explicit comparator is provided) must be <i>consistent with
equals</i>." In particular,
// ImmutableSortedSet will ignore any objects that compare equally with
an existing Set member.
// Obviously, dropping sstables whose max column timestamp happens to
be equal to another's
// is not acceptable for us. So, we use a List instead.
{noformat}
I think that comment is obsolete. Namely, it was added with CASSANDRA-2498 and
at the time the list of sstable was kept in max timestamp order at all time.
But since then, we've moved the sorting in max timestamp in CollationController
directly (which is less fragile), so the order inside DataTracker doesn't
matter anymore.
> Error in LeveledCompactionStrategy
> ----------------------------------
>
> Key: CASSANDRA-3306
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3306
> Project: Cassandra
> Issue Type: Bug
> Affects Versions: 1.0.0
> Reporter: Radim Kolar
> Assignee: Yuki Morishita
> Attachments: 0001-CASSANDRA-3306-test.patch
>
>
> during stress testing, i always get this error making leveledcompaction
> strategy unusable. Should be easy to reproduce - just write fast.
> ERROR [CompactionExecutor:6] 2011-10-04 15:48:52,179
> AbstractCassandraDaemon.java (line 133) Fatal exception in thread
> Thread[CompactionExecutor:6,5,main]
> java.lang.AssertionError
> at
> org.apache.cassandra.db.DataTracker$View.newSSTables(DataTracker.java:580)
> at
> org.apache.cassandra.db.DataTracker$View.replace(DataTracker.java:546)
> at org.apache.cassandra.db.DataTracker.replace(DataTracker.java:268)
> at
> org.apache.cassandra.db.DataTracker.replaceCompactedSSTables(DataTracker.java:232)
> at
> org.apache.cassandra.db.ColumnFamilyStore.replaceCompactedSSTables(ColumnFamilyStore.java:960)
> at
> org.apache.cassandra.db.compaction.CompactionTask.execute(CompactionTask.java:199)
> at
> org.apache.cassandra.db.compaction.LeveledCompactionTask.execute(LeveledCompactionTask.java:47)
> at
> org.apache.cassandra.db.compaction.CompactionManager$1.call(CompactionManager.java:131)
> at
> org.apache.cassandra.db.compaction.CompactionManager$1.call(CompactionManager.java:114)
> at java.util.concurrent.FutureTask$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)
> and this is in json data for table:
> {
> "generations" : [ {
> "generation" : 0,
> "members" : [ 459, 460, 461, 462, 463, 464, 465, 466, 467, 468, 469, 470,
> 471, 472, 473, 474, 475, 476, 477, 478, 479, 480, 481, 482, 483, 484 ]
> }, {
> "generation" : 1,
> "members" : [ ]
> }, {
> "generation" : 2,
> "members" : [ ]
> }, {
> "generation" : 3,
> "members" : [ ]
> }, {
> "generation" : 4,
> "members" : [ ]
> }, {
> "generation" : 5,
> "members" : [ ]
> }, {
> "generation" : 6,
> "members" : [ ]
> }, {
> "generation" : 7,
> "members" : [ ]
> } ]
> }
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