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From aaron morton <aa...@thelastpickle.com>
Subject Re: cost estimate about some Cassandra patchs
Date Sun, 28 Apr 2013 20:54:29 GMT
> Does anyone know enough of the inner working of Cassandra to tell me how much work is
needed to patch Cassandra to enable such communication vectorization/batch ?
>  
Assuming you mean "have the coordinator send multiple row read/write requests in a single
message to replicas"

Pretty sure this has been raised as a ticket before but I cannot find one now. 

It would be a significant change and I'm not sure how big the benefit is. To send the messages
the coordinator places them in a queue, there is little delay sending. Then it waits on them
async. So there may be some saving on networking but from the coordinators point of view I
think the impact is minimal. 

What is your use case?

Cheers


-----------------
Aaron Morton
Freelance Cassandra Consultant
New Zealand

@aaronmorton
http://www.thelastpickle.com

On 27/04/2013, at 4:04 AM, DE VITO Dominique <dominique.devito@thalesgroup.com> wrote:

> Hi,
>  
> We are created a new partitioner that groups some rows with **different** row keys on
the same replicas.
>  
> But neither the batch_mutate, or the multiget_slice are able to take opportunity of this
partitioner-defined placement to vectorize/batch communications between the coordinator and
the replicas.
>  
> Does anyone know enough of the inner working of Cassandra to tell me how much work is
needed to patch Cassandra to enable such communication vectorization/batch ?
>  
> Thanks.
>  
> Regards,
> Dominique
>  
>  


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