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From aaron morton <aa...@thelastpickle.com>
Subject Re: Existing column(s) not readable
Date Mon, 10 Oct 2011 20:00:40 GMT
How are they unreadable ? You need to go into some details about what is going wrong. 

What sort of read ? 
What client ? 
What is in the logging on client and server side ? 


Try turning the logging up to DEBUG on the server to watch what happens. 

Cheers
 
-----------------
Aaron Morton
Freelance Cassandra Developer
@aaronmorton
http://www.thelastpickle.com

On 10/10/2011, at 9:23 PM, Thomas Richter wrote:

> Hi,
> 
> no errors in the server logs. The columns are unreadable on all nodes at
> any consistency level (ONE, QUORUM, ALL). We started with 0.7.3 and
> upgraded to 0.7.6-2 two months ago.
> 
> Best,
> 
> Thomas
> 
> On 10/10/2011 10:03 AM, aaron morton wrote:
>> What error are you seeing  in the server logs ? Are the columns unreadable at all
Consistency Levels ? i.e. are the columns unreadable on all nodes.
>> 
>> What is the upgrade history of the cluster ? What version did it start at ? 
>> 
>> Cheers
>> 
>> 
>> -----------------
>> Aaron Morton
>> Freelance Cassandra Developer
>> @aaronmorton
>> http://www.thelastpickle.com
>> 
>> On 10/10/2011, at 7:42 AM, Thomas Richter wrote:
>> 
>>> Hi,
>>> 
>>> here is some further information. Compaction did not help, but data is
>>> still there when I dump the row with sstable2json.
>>> 
>>> Best,
>>> 
>>> Thomas
>>> 
>>> On 10/08/2011 11:30 PM, Thomas Richter wrote:
>>>> Hi,
>>>> 
>>>> we are running a 3 node cassandra (0.7.6-2) cluster and some of our
>>>> column families contain quite large rows (400k+ columns, 4-6GB row size).
>>>> Replicaton factor is 3 for all keyspaces. The cluster is running fine
>>>> for several months now and we never experienced any serious trouble.
>>>> 
>>>> Some days ago we noticed, that some previously written columns could not
>>>> be read. This does not always happen, and only some dozen columns out of
>>>> 400k are affected.
>>>> 
>>>> After ruling out application logic as a cause I dumped the row in
>>>> question with sstable2json and the columns are there (and are not marked
>>>> for deletion).
>>>> 
>>>> Next thing was setting up a fresh single node cluster and copying the
>>>> column family data to that node. Columns could not be read either.
>>>> Right now I'm running a nodetool compact for the cf to see if data could
>>>> be read afterwards.
>>>> 
>>>> Is there any explanation for such behavior? Are there any suggestions
>>>> for further investigation?
>>>> 
>>>> TIA,
>>>> 
>>>> Thomas
>>> 
>> 
> 


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