I am using mongodb in codeigniter. collections \'mtb\' \'road\' \'minivelo\' php $map = new MongoCode(\' function(){
MapReduce has been shown to be powerful solve problem with large data sets in a parallel/distributed way.
I need a variable that shared between reduce tasks and each of reduce tasks ca开发者_运维百科n read and write on it atomically.
I am using Cassandra with Hadoop for input and output. During the output reduce job, I got an error: 2011-08-10 03:54:04,326 WARN org.apache.hadoop.mapred.Child: Error running child
I am using Hadoop + Cassandra. I use setInputSplitSize(1000) to not overload mappers (and receive out of heap memory) as default it is 64K. All 开发者_StackOverflow社区together I have only 2M lines to
Here is an example: Is it possible to have same mapper run against multiple reducers at the same time? like
I would like to use MongoDB as the backend for the analytics system I am building. One of the main advantages of using MongoDB is the built-in map reduce.
I have been using Hadoop quite a while now. After some time I realized I n开发者_高级运维eed to chain Hadoop jobs, and have some type of workflow. I decided to use Oozie , but couldn\'t find much of i
开发者_如何学GoI want to print each step of my \"map\" after its execution on the console. Something like
I\'ve never tried map/reduce. How would I get the oldest of each type of animal? My data is like this: [
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