curl -XPUT 'http://127.0.0.1:9200/test/?pretty=1'  -d '
{
   "mappings" : {
      "test" : {
         "properties" : {
            "foo" : {
               "type" : "nested"
            }
         }
      }
   }
}
'

curl -XPOST 'http://127.0.0.1:9200/test/test?pretty=1'  -d '
{
   "foo" : [
      {
         "val" : 10,
         "tag" : "foo"
      },
      {
         "val" : 20,
         "tag" : "bar"
      }
   ]
}
'

curl -XGET 'http://127.0.0.1:9200/test/test/_search?pretty=1'  -d '
{
   "sort" : [
      {
         "foo.val" : {
            "sort_order" : "asc",
            "sort_mode" : "sum"
         }
      }
   ]
}
'

# {
#    "hits" : {
#       "hits" : [
#          {
#             "_source" : {
#                "foo" : [
#                   {
#                      "tag" : "foo",
#                      "val" : 10
#                   },
#                   {
#                      "tag" : "bar",
#                      "val" : 20
#                   }
#                ]
#             },
#             "sort" : [
#                10
#             ],
#             "_score" : null,
#             "_index" : "test",
#             "_id" : "kHkGLjyASUycZveKsg9Low",
#             "_type" : "test"
#          }
#       ],
#       "max_score" : null,
#       "total" : 1
#    },
#    "timed_out" : false,
#    "_shards" : {
#       "failed" : 0,
#       "successful" : 5,
#       "total" : 5
#    },
#    "took" : 4
# }


curl -XGET 'http://127.0.0.1:9200/test/test/_search?pretty=1'  -d '
{
   "sort" : [
      {
         "foo.val" : {
            "sort_order" : "asc",
            "sort_mode" : "avg"
         }
      }
   ]
}
'

# {
#    "hits" : {
#       "hits" : [
#          {
#             "_source" : {
#                "foo" : [
#                   {
#                      "tag" : "foo",
#                      "val" : 10
#                   },
#                   {
#                      "tag" : "bar",
#                      "val" : 20
#                   }
#                ]
#             },
#             "sort" : [
#                10
#             ],
#             "_score" : null,
#             "_index" : "test",
#             "_id" : "kHkGLjyASUycZveKsg9Low",
#             "_type" : "test"
#          }
#       ],
#       "max_score" : null,
#       "total" : 1
#    },
#    "timed_out" : false,
#    "_shards" : {
#       "failed" : 0,
#       "successful" : 5,
#       "total" : 5
#    },
#    "took" : 2
# }