A little feedback,
I scrubbed on each server and I haven't seen this error again. The load on each server eems to be correct.
nodetool compactionstats shows  boat-load of "Scrub" at 100% on my 3rd node but not on the 2 others.
I left it that way and haven't restart yet.

2011/9/26 aaron morton <aaron@thelastpickle.com>
Looks like a mismatch between the key the index says should be at a certain position in the date file and the key that is actually there. 

I've not checked but scrub *may* fix this this. Try it and see. 

(repair is for repairing consistency between nodes, scrub fixes local issues with data. )

Cheers
 
-----------------
Aaron Morton
Freelance Cassandra Developer
@aaronmorton

On 26/09/2011, at 12:53 PM, Philippe wrote:

Juste did
Could there be data corruption or will repairs do this?

Thanks

Le 25 sept. 2011 15:30, "Jonathan Ellis" <jbellis@gmail.com> a écrit :
> Assertion errors are bugs, so that should worry you.
>
> However, I'd upgrade before filing a ticket. There were a lot of
> fixes in 0.8.5.
>
> On Sun, Sep 25, 2011 at 2:27 AM, Philippe <watcherfr@gmail.com> wrote:
>> Hello,
>> I've seen a couple of these in my logs, running 0.8.4.
>> This is a RF=3, 3-node cluster. 2 nodes including this one are on 0.8.4 and
>> one is on 0.8.5
>>
>> The node is still functionning hours later. Should I be worried ?
>>
>> Thanks
>>
>> ERROR [ReadStage:94911] 2011-09-24 22:40:30,043 AbstractCassandraDaemon.java
>> (line 134) Fatal exception in thread Thread[ReadStage:94911,5,main]
>> java.lang.AssertionError:
>> DecoratedKey(Token(bytes[0000224ceb80b5fb11e00000848783ceb9bf0000000000000002ffffffffffffff33]),
>> 0000224ceb80b5fb11e00000848783ceb9bf0000000000000002ffffffffffffff33) !=
>> DecoratedKey(Token(bytes[038453154cb00000005f14]), 038453154cb00000005f14)
>> in /var/lib/cassandra/data/XXXXXXXXX/PUBLIC_MONTHLY_20-g-10634-Data.db
>>         at
>> org.apache.cassandra.db.columniterator.SSTableSliceIterator.<init>(SSTableSliceIterator.java:59)
>>         at
>> org.apache.cassandra.db.filter.SliceQueryFilter.getSSTableColumnIterator(SliceQueryFilter.java:66)
>>         at
>> org.apache.cassandra.db.filter.QueryFilter.getSSTableColumnIterator(QueryFilter.java:80)
>>         at
>> org.apache.cassandra.db.ColumnFamilyStore.getTopLevelColumns(ColumnFamilyStore.java:1315)
>>         at
>> org.apache.cassandra.db.ColumnFamilyStore.cacheRow(ColumnFamilyStore.java:1182)
>>         at
>> org.apache.cassandra.db.ColumnFamilyStore.getColumnFamily(ColumnFamilyStore.java:1222)
>>         at
>> org.apache.cassandra.db.ColumnFamilyStore.getColumnFamily(ColumnFamilyStore.java:1169)
>>         at org.apache.cassandra.db.Table.getRow(Table.java:385)
>>         at
>> org.apache.cassandra.db.SliceByNamesReadCommand.getRow(SliceByNamesReadCommand.java:58)
>>         at
>> org.apache.cassandra.service.StorageProxy$LocalReadRunnable.runMayThrow(StorageProxy.java:642)
>>         at
>> org.apache.cassandra.service.StorageProxy$DroppableRunnable.run(StorageProxy.java:1107)
>>         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)
>> ERROR [ReadStage:94936] 2011-09-24 22:40:30,042 AbstractCassandraDaemon.java
>> (line 134) Fatal exception in thread Thread[ReadStage:94936,5,main]
>> java.lang.AssertionError: DecoratedKey(Token(bytes[]), ) !=
>> DecoratedKey(Token(bytes[038453154c900000005f14]), 038453154c900000005f14)
>> in /var/lib/cassandra/data/XXXXXXXXX/PUBLIC_MONTHLY_20-g-10634-Data.db
>>         at
>> org.apache.cassandra.db.columniterator.SSTableSliceIterator.<init>(SSTableSliceIterator.java:59)
>>         at
>> org.apache.cassandra.db.filter.SliceQueryFilter.getSSTableColumnIterator(SliceQueryFilter.java:66)
>>         at
>> org.apache.cassandra.db.filter.QueryFilter.getSSTableColumnIterator(QueryFilter.java:80)
>>         at
>> org.apache.cassandra.db.ColumnFamilyStore.getTopLevelColumns(ColumnFamilyStore.java:1315)
>>         at
>> org.apache.cassandra.db.ColumnFamilyStore.cacheRow(ColumnFamilyStore.java:1182)
>>         at
>> org.apache.cassandra.db.ColumnFamilyStore.getColumnFamily(ColumnFamilyStore.java:1222)
>>         at
>> org.apache.cassandra.db.ColumnFamilyStore.getColumnFamily(ColumnFamilyStore.java:1169)
>>         at org.apache.cassandra.db.Table.getRow(Table.java:385)
>>         at
>> org.apache.cassandra.db.SliceByNamesReadCommand.getRow(SliceByNamesReadCommand.java:58)
>>         at
>> org.apache.cassandra.service.StorageProxy$LocalReadRunnable.runMayThrow(StorageProxy.java:642)
>>         at
>> org.apache.cassandra.service.StorageProxy$DroppableRunnable.run(StorageProxy.java:1107)
>>         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)
>> ERROR [ReadStage:94713] 2011-09-24 22:40:30,041 AbstractCassandraDaemon.java
>> (line 134) Fatal exception in thread Thread[ReadStage:94713,5,main]
>> java.lang.AssertionError:
>> DecoratedKey(Token(bytes[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]),
>> 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)
>> != DecoratedKey(Token(bytes[038451bfeeb00000005f14]),
>> 038451bfeeb00000005f14) in
>> /var/lib/cassandra/data/XXXXXXXXX/PUBLIC_MONTHLY_20-g-12305-Data.db
>>
>>
>>
>>
>
>
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of DataStax, the source for professional Cassandra support
> http://www.datastax.com