mongoDB + ruby + map_reduceのサンプル

Gemfile

source "https://rubygems.org"
gem "mongo"
gem "bson_ext"

mongodb-first-trial.rb

require 'bundler/setup'
require 'mongo'

p Time.new

N = 65565 * 10

conn = Mongo::Connection.new
test = conn.db('test')
foo  = test.collection('foo')

# foo.drop();

N.times { |i|
  doc = { 'userid' => "hello world #{i}", 'cdate' => Time.new }
  foo.insert(doc)
}
# foo.find.each { |r| p r }

map = %Q{
  function() {
    var t = new Date(this.cdate);
    var y = t.getFullYear();
    var m = t.getMonth() + 1;
    var d = t.getDate();

    var k = [y, ('0' + m).slice(-2), ('0' + d).slice(-2)].join('/');

    emit(k, 1);
  }
}

reduce = %Q{
  function(key, values) {
    var sum = 0;
    values.forEach(function(v) { sum = sum + v });
    return sum;
  }
}

stat = test.collection('stat')
stat.drop();
p Time.new
foo.map_reduce(map, reduce, { 'query' => { 'cdate' => { '$exists' => true } }, 'out' => 'stat' });
p Time.new
stat.find.each { |r| p r }

mongodb-second-trial.rb

#
# http://api.mongodb.org/ruby/1.9.2/
#

require 'bundler/setup'
require 'mongo'

include Mongo

client = MongoClient.new('localhost', 27017)

p client.database_names

client.database_info.each { |info| puts info.inspect }

db = client.db("test")

foo = db["foo"]

order = [
  ['cdate' , DESCENDING],
  ['userid', DESCENDING],
]

opts = {
  :limit => 12,
  :sort  => order,
}

foo.find({}, opts).each { |doc| p doc }