nodejs MapReduce
发布于 10 年前 作者 lodengo 6705 次浏览 最后一次编辑是 8 年前 来自 分享

nodejs map-reduce

CouchDB-style-like map-reduce:CouchDB MapReduce

usage: world count example

  var fs = require('fs');
	var worldCounter = new MapReduce({
	map: function(chunk){		
		chunk.toString().split(/\W+|\d+/).forEach(function(world){			
			world && this.emit(world.toLowerCase(), 1);
		}, this);
	},
	reduce: function(key, values){
		return this.count(values);
	},
	inputs: fs.readdirSync('./').map(fs.createReadStream),
	fork: false //should forEach input fork a cluster.worker to do map job or not
});

worldCounter.run(function(result){
	console.log(result);
});

more think:

  1. should do reduce during mapping rather than wait until mapping done?
  2. use nodejs ChildProcess/Cluster fork to do map/reduce job?
  3. for processing and generating large data sets with a parallel, distributed algorithm on a cluster? you may look for Hadoop
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