trouble with multi_field with tire

gistfile1.rb

#encoding: utf-8
require 'rubygems'
require 'tire'
#require 'json'
require 'active_support/core_ext/object/to_query'
require 'active_support/core_ext/object/to_param'

Tire.configure { logger 'elasticsearch.log', :level => 'debug' }
tire = Tire.index 'path' do
  delete
  conf = {
    settings: {
      analysis: {
        tokenizer: {
          my_path_tokenizer: {
            type: 'path_hierarchy',
            delimiter: '.'
          }
        },
        analyzer: {
          my_path: {
            type: 'custom',
            tokenizer: 'my_path_tokenizer',
            filter: ['lowercase']
          },
          my_tokens: {
            type: 'pattern',
            pattern: '[.]'
          }
        }
      }
    },
    mappings: {
      key: {
        properties: {
          key: {
            type: 'multi_field',
            fields: {
              raw: {
                type: 'string',
                analyzer: 'keyword',
                include_in_all: false
              },
              key: { # see https://gist.github.com/1042483
                type: 'string',
                analyzer: 'my_tokens',
                include_in_all: true
              },
              path: {
                type: 'string',
                analyzer: 'my_path',
                include_in_all: true
              }
            }
          }
        }
      }
    }
  }

  create conf
  import %w{worg.elasticsearch.info org.elasticsearch.src org.lucene.info}.map{|key| {id: key, key: key, type:'key'} }
  refresh
end

p 'path', tire.analyze("org.elasticsearch.info", analyzer: 'my_path')['tokens'].map{|token| token['token']}
p 'tokens', tire.analyze("org.elasticsearch.info", analyzer: 'my_tokens')['tokens'].map{|token| token['token']}

s = Tire.search 'path' do
  query do
    string 'key:elasticsearch'
  end
end
p "search key:elasticsearch", s.results.length
# 1

s = Tire.search 'path' do
  query do
    string 'elasticsearch'
  end
end
p "search elasticsearch", s.results.length
# 0