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From Boris Yen <yulin...@gmail.com>
Subject Re: Why do Digest Queries return hash instead of timestamp?
Date Wed, 13 Jul 2011 12:20:51 GMT
For a specific column, If there are two versions with the same timestamp,
the value of the column is used to break the tie.

if v1.value().compareTo(v2.value()) < 0, it means that v2 wins.

On Wed, Jul 13, 2011 at 7:13 PM, David Boxenhorn <david@citypath.com> wrote:

> How would you know which data is correct, if they both have the same
> timestamp?
>
> On Wed, Jul 13, 2011 at 12:40 PM, Boris Yen <yulinyen@gmail.com> wrote:
>
>> I can only say, "data" does matter, that is why the developers use hash
>> instead of timestamp. If hash value comes from other node is not a match, a
>> read repair would perform. so that correct data can be returned.
>>
>>
>> On Wed, Jul 13, 2011 at 5:08 PM, David Boxenhorn <david@citypath.com>wrote:
>>
>>> If you have to pieces of data that are different but have the same
>>> timestamp, how can you resolve consistency?
>>>
>>> This is a pathological situation to begin with, why should you waste
>>> effort to (not) solve it?
>>>
>>> On Wed, Jul 13, 2011 at 12:05 PM, Boris Yen <yulinyen@gmail.com> wrote:
>>>
>>>> I guess it is because the timestamp does not guarantee data consistency,
>>>> but hash does.
>>>>
>>>> Boris
>>>>
>>>>
>>>> On Wed, Jul 13, 2011 at 4:27 PM, David Boxenhorn <david@citypath.com>wrote:
>>>>
>>>>> I just saw this
>>>>>
>>>>> http://wiki.apache.org/cassandra/DigestQueries
>>>>>
>>>>> and I was wondering why it returns a hash of the data. Wouldn't it be
>>>>> better and easier to return the timestamp? You don't really care what
the
>>>>> data is, you only care whether it is more or less recent than another
piece
>>>>> of data.
>>>>>
>>>>
>>>>
>>>
>>
>

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