Test date in milliseconds since epoch

test_date_millis.json

DELETE test
PUT test
{
  "settings": {
    "number_of_shards": 1
  },
  "mappings": {
    "doc": {
      "properties": {
        "mydate": {
          "type": "date"
        }
      }
    }
  }
}
PUT test/doc/1
{
  "mydate": 1404831198707
}
GET test/_search
{
  "aggs": {
    "by_year": {
      "date_histogram": {
        "field": "mydate",
        "interval": "month"
      }
    }
  }
}