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MapReduce, mail # user - Re: Query mongodb


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RE: Query mongodb
John Lilley 2013-01-16, 14:56
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<http://cloudfront.blogspot.com>

On Wed, Jan 16, 2013 at 8:10 PM, John Lilley <[EMAIL PROTECTED]<mailto:[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]<mailto:[EMAIL PROTECTED]>]
Sent: Wednesday, January 16, 2013 3:29 AM
To: [EMAIL PROTECTED]<mailto:[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<http://cloudfront.blogspot.com>

On Wed, Jan 16, 2013 at 3:50 PM, Panshul Whisper <[EMAIL PROTECTED]<mailto:[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.