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From Alexander Frolov <alexndr.fro...@gmail.com>
Subject Re: Basic questions about Giraph internals
Date Fri, 07 Feb 2014 11:39:31 GMT
On Fri, Feb 7, 2014 at 2:30 PM, Claudio Martella <claudio.martella@gmail.com
> wrote:

>
>
>
> On Fri, Feb 7, 2014 at 9:44 AM, Alexander Frolov <alexndr.frolov@gmail.com
> > wrote:
>
>>  Thank you, I will try to do this. As I understood I should set number
>>> of threads manually through Giraph API.
>>>
>>> BTW, what is conceptual difference between running multiple workers on
>>> the TaskTracker and running single worker and multiple threads? In terms of
>>> vertex fetching, memory sharing etc.
>>>
>>
> Basically, better usage of resources: one single JVM, no duplication of
> core data structures, less netty threads and communication points, more
> locality (less messages over the network), less actors accessing zookeeper
> etc.
>
>
>>
>>>  Also I would like to ask how message transfer between vertices is
>> implemented in terms of Hadoop primitives? Source code reference will be
>> enough.
>>
>
> Communication does not happen via Hadoop primitives, but ad-hoc via netty.
>

Ok. It seams that Hadoop has minimalistic influence on Giraph application
execution after graph is loaded into memory (that is mapping is done).

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