Don't trust querying mongo directly...

proud.rb

require 'rubygems'
require 'sequel'
require 'bson'
require 'set'

class Time
  def beginning_of_month
    Time.utc(self.year, self.month, 1)
  end
end

DB = Sequel.connect('postgres://foo:bar@localhost/builder')
BUFFER_LENGTH = 1000

months = Hash.new(Set.new)
counter = 0
buffer = {}
io = File.new('conversions.bson')
while(!io.eof?) do
  ob = BSON.read_bson_document(io)
  next unless ob["finished_at"]
  month = ob["finished_at"].beginning_of_month
  if months[month].add?(ob["worker_id"]).nil?
    DB["UPDATE conversions SET earnings = earnings + ? WHERE worker_id = ? AND month = ?", ob["amount"], ob["worker_id"], month]
  elsif buffer.length >= BUFFER_LENGTH
    DB[:conversions].insert_multiple buffer.map do |k,v|
      v.merge(:worker_id => k[0], :month => k[1])
    end
    buffer = {}
  else
    buffer[[ob["worker_id"], month]] ||= Hash.new(0)
    buffer[[ob["worker_id"], month]][:earnings] += ob["amount"]
    buffer[[ob["worker_id"], month]][:channel] = ob["external_type"]
  end
  counter += 1
  puts "#{counter}" if counter % 10000 == 0
  if counter % 100 == 0
    $stdout.print "."
    $stdout.flush
  end 
end