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From Zhong Li <...@voxeo.com>
Subject Re: How to migrate any relational database to Cassandra
Date Sun, 08 Aug 2010 02:46:57 GMT
Yes, I use OrderPreservngPartitioner, the token considers datacenter+ip 
+function+timestamp+recordId+...

On Aug 7, 2010, at 10:36 PM, Jonathan Ellis wrote:

> are you using OrderPreservingPartitioner then?
>
> On Sat, Aug 7, 2010 at 10:32 PM, Zhong Li <zli@voxeo.com> wrote:
>> Here is just my personal experiences.
>>
>> I recently use Cassandra to implement a system cross 5 datacenters.  
>> Because
>> it is impossible to do it in SQL Database at low cost, Cassandra  
>> helps.
>>
>> Cassandra is all about indexing, there is no relationship  
>> naturally, you
>> have to use indexing to keep all relationships. This is fine,  
>> because you
>> can add new index when you want.
>>
>> The big pain is the token. Only one token you can choose for a  
>> node, all
>> system have to adopt same rule to create index. It is huge huge pain.
>>
>> If Cassandra can implement token at CF level, it is much nature and  
>> easy for
>> us to implement a system.
>>
>> Best,
>>
>> Zhong
>>
>>
>> On Aug 6, 2010, at 9:23 PM, Peter Harrison wrote:
>>
>>> On Sat, Aug 7, 2010 at 6:00 AM, sonia gehlot  
>>> <sonia.gehlot@gmail.com>
>>> wrote:
>>>
>>>> Can you please help me how to move forward? How should I do all  
>>>> the setup
>>>> for this?
>>>
>>> My view is that Cassandra is fundamentally different from SQL  
>>> databases.
>>> There
>>> may be artefact's which are superficially similar between the two  
>>> systems,
>>> but
>>> I guess I'm thinking of a move to Cassandra like my move from  
>>> dBase to
>>> Delphi;
>>> in other words there were concepts which modified how you write
>>> applications.
>>>
>>> Now, you can do something similar to a SQL database, but I don't  
>>> think you
>>> would
>>> be leveraging the features of Cassandra. That said, I think there  
>>> will be
>>> a new
>>> generation of abstraction tools that will make modeling easier.
>>>
>>> A perhaps more practical answer: there is no one to one mapping  
>>> between
>>> SQL
>>> and Cassandra.
>>
>>
>
>
>
> -- 
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of Riptano, the source for professional Cassandra support
> http://riptano.com


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