nodejs MapReduce
发布于 4个月前 作者 lodengo 350 次浏览 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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