Hello, Don’t get me wrong here….just as per my understanding after reading your reply…. Are you telling me about MongoDb instances on multiple nodes????
I am talking of a single mongoDb instance/server having multiple collection in it….(say multiple tables). Please help me in understanding. Abhishek From: Corey Nolet [mailto:cjno...@gmail.com] Sent: Friday, September 11, 2015 7:58 PM To: Sandeep Giri Cc: Mishra, Abhishek; user@spark.apache.org; d...@spark.apache.org Subject: Re: MongoDB and Spark Unfortunately, MongoDB does not directly expose its locality via its client API so the problem with trying to schedule Spark tasks against it is that the tasks themselves cannot be scheduled locally on nodes containing query results- which means you can only assume most results will be sent over the network to the task that needs to process it. This is bad. The other reason (which is also related to the issue of locality) is that I'm not sure if there's an easy way to spread the results of a query over multiple different clients- thus you'd probably have to start your Spark RDD with a single partition and then repartition. What you've done at that point is you've taken data from multiple mongodb nodes and you've collected them on a single node just to re-partition them, again across the network, onto multiple nodes. This is also bad. I think this is the reason it was recommended to use MongoDB's mapreduce because they can use their locality information internally. I had this same issue w/ Couchbase a couple years back- it's unfortunate but it's the reality. On Fri, Sep 11, 2015 at 9:34 AM, Sandeep Giri <sand...@knowbigdata.com<mailto:sand...@knowbigdata.com>> wrote: I think it should be possible by loading collections as RDD and then doing a union on them. Regards, Sandeep Giri, +1 347 781 4573<tel:%2B1%20347%20781%204573> (US) +91-953-899-8962 (IN) www.KnowBigData.com.<http://KnowBigData.com.> Phone: +1-253-397-1945<tel:%2B1-253-397-1945> (Office) [linkedin icon]<https://linkedin.com/company/knowbigdata>[other site icon]<http://knowbigdata.com> [facebook icon] <https://facebook.com/knowbigdata> [twitter icon] <https://twitter.com/IKnowBigData> On Fri, Sep 11, 2015 at 3:40 PM, Mishra, Abhishek <abhishek.mis...@xerox.com<mailto:abhishek.mis...@xerox.com>> wrote: Anything using Spark RDD’s ??? Abhishek From: Sandeep Giri [mailto:sand...@knowbigdata.com<mailto:sand...@knowbigdata.com>] Sent: Friday, September 11, 2015 3:19 PM To: Mishra, Abhishek; user@spark.apache.org<mailto:user@spark.apache.org>; d...@spark.apache.org<mailto:d...@spark.apache.org> Subject: Re: MongoDB and Spark use map-reduce. On Fri, Sep 11, 2015, 14:32 Mishra, Abhishek <abhishek.mis...@xerox.com<mailto:abhishek.mis...@xerox.com>> wrote: Hello , Is there any way to query multiple collections from mongodb using spark and java. And i want to create only one Configuration Object. Please help if anyone has something regarding this. Thank You Abhishek
