DistRedis#mget.out.txt

## Output

Node: Keys
6379: ["120"]
6380: ["119", "110", "111", "114", "105", "115", "106", "107", "118"]
6381: ["102", "112", "103", "113", "104", "100", "101"]
6382: ["116", "117", "108", "109"]

First key from each node
["119", "102", "116", "120"]

# before patch
mget(key_from_each_node)  => [nil, nil, nil, "120"]
mget(*key_from_each_node) => ["119", nil, nil, nil]

# after patch
mget(key_from_each_node)  => ["119", "120", "116", "102"]
mget(*key_from_each_node) => ["119", "120", "116", "102"]

DistRedis#mget.rb

require 'dist_redis'

Redis.module_eval { attr_accessor :port }

dr = DistRedis.new(:hosts => %w(localhost:6379 localhost:6380 localhost:6381 localhost:6382'), :db => 10)

## setup
dr.delete_cloud!
100.upto(120) { |i| dr.set(i, i) }

## capture & print our key distribution
key_distribution = {}
puts "\nNode: Keys"
dr.ring.nodes.each { |node| 
  port = node.port
  keys = node.keys('*')
  key_distribution[port] = keys
  puts "#{ port }: #{ keys.inspect }" 
}

puts "\nFirst key from each node"
key_from_each_node = key_distribution.values.collect(&:first)
p key_from_each_node # => ["119", "102", "116", "120"]

puts "\n# before patch"
print "mget(key_from_each_node)  => #{ dr.mget(key_from_each_node).inspect  }\n"
print "mget(*key_from_each_node) => #{ dr.mget(*key_from_each_node).inspect }\n"

# improvement??
DistRedis.module_eval do 

  def mget(*keyz)
    results = {}
    kbn = keys_by_node(keyz)
    kbn.each do |node, node_keyz| 
      node.mapped_mget(*node_keyz).each do |k, v|
        results[k] = v
      end
    end
    keyz.flatten.map { |k| results[k] }
  end

  private

  def keys_by_node(*keyz)
    keyz.flatten.inject({}) do |kbn, k|
      node = node_for_key(k)
      next if kbn[node] && kbn[node].include?(k)
      kbn[node] ||= []
      kbn[node] << k 
      kbn
    end
  end

end

puts "\n# after patch"
print "mget(key_from_each_node)  => #{ dr.mget(key_from_each_node).inspect  }\n"
print "mget(*key_from_each_node) => #{ dr.mget(*key_from_each_node).inspect }\n"