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Re: Query mongodb
Hadoop knows about files and blocks so you can achieve data locality if you are accessing files directly

I think, In your case you'll have to develop your own logic that can take advantage of it

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On Jan 16, 2013, at 6:56 AM, John Lilley <[EMAIL PROTECTED]> wrote:

> Um, I think you and I are talking about the same thing, but maybe not?
>  
> Certainly HBase/MongoDB are HDFS-aware, so I would expect that if I am a client program running outside of the Hadoop cluster and I do a query, the database tools will construct query processing such that data is read and processed in an optimal fashion (using MapReduce?), before the aggregated information is shipped to me on the client side.
>  
> The question I was asking is a little different although hopefully the answer is just as simple.  Can I write mapper/reducer that queries HBase/MongoDB and have MR schedule my mappers such that each mapper is receiving tuples that have been read in a locality-aware fashion?
>  
> john
>  
> From: Mohammad Tariq [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, January 16, 2013 7:47 AM
> To: [EMAIL PROTECTED]
> Subject: Re: Query mongodb
>  
> MapReduce framework tries its best to run the jobs on the nodes
> where  data is located. It is its fundamental nature. You don't have
> to do anything extra.
>  
> *I am sorry if I misunderstood the question.
>  
>
> Warm Regards,
> Tariq
> https://mtariq.jux.com/
> cloudfront.blogspot.com
>  
>
> On Wed, Jan 16, 2013 at 8:10 PM, John Lilley <[EMAIL PROTECTED]> wrote:
> How does one schedule mappers to read MongoDB or HBase in a data-locality-aware fashion?
> -john
>  
> From: Mohammad Tariq [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, January 16, 2013 3:29 AM
> To: [EMAIL PROTECTED]
> Subject: Re: Query mongodb
>  
> Yes. You can use MongoDB-Hadoop adapter to achieve that. Through this adapter you can pull the data, process it and push it back to your MongoDB backed datastore by writing MR jobs.
>  
> It is also 100% possible to query Hbase or JSON files, or anything else for that matter, stored in HDFS.
>
> Warm Regards,
> Tariq
> https://mtariq.jux.com/
> cloudfront.blogspot.com
>  
>
> On Wed, Jan 16, 2013 at 3:50 PM, Panshul Whisper <[EMAIL PROTECTED]> wrote:
> Hello,
> Is it possible or how is it possible to query mongodb directly from hadoop.
>
> Or is it possible to query hbase or json files stored in hdfs in a similar way as we can query the json documents in mongodb.
>
> Suggestions please.
>
> Thank you.
> Regards,
> Panshul.
>
>  
>