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any one can give sample code from mongodb to rdbs ... I tried already , fetching data from mongodb and output store in mongodb.For that i knew how to do hadoop configuration in java job.

And i want to know three things...

  1. which hadoop version support both mongodb and rdbs?
  2. Is it possible to use multiple collections as input...? If possible, how we can do that?
  3. I tried mongodb query in hadoop,It's working fine.But when i defined sort or limit...It is not working properly..even it's not fetching data from mongodb...
Stennie
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Coe Lnt
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    Can you provide some more information, such as the versions of Hadoop and the MongoDB Hadoop Connector that you are using? An example of your query and any specific errors might also help someone work out what is not working. – Stennie Sep 03 '12 at 07:28

1 Answers1

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1. which hadoop version support both mongodb and rdbs?

I believe that all versions of Hadoop supporting MongoDB also support RDBMS (the RDBMS implementations predate MongoDB).

For supported versions of Hadoop to use with MongoDB, see: Building the Adapter. Check the version information as some Hadoop versions do not support the Streaming Connector (i.e. if you want to write your jobs in non-JVM languages such as Python).

2. Is it possible to use multiple collections as input...?
If possible, how we can do that?

MongoDB Hadoop Connector v1.0.0 does not support multiple collections as input, but there are a few folks in the community working on this (see: Feature/multiple inputs).

3. I tried mongodb query in hadoop,It's working fine. But when i defined
sort or limit... It is not working properly..even it's not fetching data
from mongodb...

Can you provide an example of how/where you provided these options? Are you referring to the mongo.input.sort and mongo.input.limit properties?

You may want to try enabling the Database Profiler in MongoDB to confirm the queries are being sent:

 db.setProfilingLevel(2)
Stennie
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