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From Zhong Li <...@voxeo.com>
Subject Re: data deleted came back after 9 days.
Date Mon, 23 Aug 2010 03:09:02 GMT
Today, I checked all nodes data and logs, there are very few nodes  
reported connections up/down. I found some data on each nodes which I  
don't understand.

The ReplicationFactor is 2, write Consistency Level is one.  Example,  
the ring like Node1(Token1)->Node2(Token2)->Node3(Token3)->.......  
Node1 has token1, suppose all data with key as token1 should be  on  
Node1 and Node2, but why I can find some Node1/Node2 data on Node3  
also? I dumped the data on Node3 to my local, red them and found some  
Node1/Node2's data on the Node3  and those data should be deleted.

Why Node3 has Node1/Node2's data?

Thanks.


On Aug 18, 2010, at 10:44 AM, Jonathan Ellis wrote:

> HH would handle it if it were a FD false positive, but if a node
> actually does go down then it can miss writes before HH kicks in.
>
> On Wed, Aug 18, 2010 at 9:30 AM, Raj N <raj.cassandra@gmail.com>  
> wrote:
>> Guys,
>>     Correct me if I am wrong. The whole problem is because a node  
>> missed an
>> update when it was down. Shouldn’t HintedHandoff take care of this  
>> case?
>>
>> Thanks
>> -Raj
>>
>> -----Original Message-----
>> From: Jonathan Ellis [mailto:jbellis@gmail.com]
>> Sent: Wednesday, August 18, 2010 9:22 AM
>> To: user@cassandra.apache.org
>> Subject: Re: data deleted came back after 9 days.
>>
>> Actually, tombstones are read repaired too -- as long as they are not
>> expired.  But nodetool repair is much less error-prone than relying  
>> on RR
>> and your memory of what deletes you issued.
>>
>> Either way, you'd need to increase GCGraceSeconds first to make the
>> tombstones un-expired first.
>>
>> On Wed, Aug 18, 2010 at 12:43 AM, Benjamin Black <b@b3k.us> wrote:
>>> On Tue, Aug 17, 2010 at 7:49 PM, Zhong Li <zli@voxeo.com> wrote:
>>>> Those data were inserted one node, then deleted on a remote node in
>>>> less than 2 seconds. So it is very possible some node lost  
>>>> tombstone
>>>> when connection lost.
>>>> My question, is a ConstencyLevel.ALL read can retrieve lost  
>>>> tombstone
>>>> back instead of repair?
>>>>
>>>
>>> No.  Read repair does not replay operations.  You must run nodetool
>>> repair.
>>>
>>>
>>> b
>>>
>>
>>
>>
>> --
>> Jonathan Ellis
>> Project Chair, Apache Cassandra
>> co-founder of Riptano, the source for professional Cassandra support
>> http://riptano.com
>>
>
>
>
> -- 
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of Riptano, the source for professional Cassandra support
> http://riptano.com


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