I have inherited a mapreduce codebase which mainly calculates the number of unique user IDs seen over time for different ads. To me it doesn\'t look like it is being done very efficiently, and I would
I am using Avro 1.4.0 to read some data out of S3 via the Python avro bindings and the boto S3 library. Whe开发者_如何学JAVAn I open an avro.datafile.DataFileReader on the file like objects returned b
I have set up Hadoop on my laptop and ran the example program given in the installation guide successfully. But, I am not able to run a program.
Grep seems not to be working for hadoop streaming For: hadoop jar /usr/local/hadoop-0.20.2/contrib/streaming/hadoop-0.20.2-streaming.jar -input /user/root/tmp2/user.data -output /user/root/selected_d
Is there a wa开发者_Go百科y in Hadoop to ensure that every reducer gets only one key that is output by the mapper ?This question is a bit unclear for me. But I think I have a pretty good idea what you
If I understand the Hadoop ecosystem correctly, I can run my MapReduce jobs sourcing data from either HDFS or HBase. Assuming the previous assumption is correct, why would I choose one over the other?
I have some experience with Lucene, I\'m trying to understand how the data is actually stored in slave server in Hadoop framework?
How do I create a hadoop jar that includes all dependencies in the lib folder using Gradle? Basically开发者_运维知识库, similar to what fatjar does.Figured it out! Hadoop looks for libraries inside th
We can provide input files to the mapper as FileInputFormat.setInputPaths(conf, inputPath); Is it possible to pass a reference to memory say a DOM tree constructed using a DOM parser
I have launched a small cluster of two nodes and noticed that the master stays completely idle while the slave does all the work. I was wondering what is the way to let master run some of the tasks. I
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