搜索日期范围显示奇怪的结果

Question

当我这样查询数据集时：

curl -X GET "localhost:9200/_search" -H 'Content-Type: application/json' -d'
{
"query": {
        "range" : {
            "time_written" : {
                "gte": "2009-01-01",
                "lte": "2011-01-01",
                "format": "yyyy-MM-dd"
            }
        }
    }
}
'

我用time_writing 2010-10-12找到了结果

但是使用此查询：

curl -X GET "localhost:9200/_search" -H 'Content-Type: application/json' -d'
{
"query": {
        "range" : {
                "time_written" : {
                    "gte": "2010-01-01",
                    "lte": "2011-01-01",
                    "format": "yyyy-MM-dd"
                }
        }
    }
}
'

找不到带有time_writing 2010-10-12的结果。知道为什么会这样吗？

更新

映射：

{
    "textobject-index":{
        "mappings":{
            "doc":{
                "properties":{
                    "main_text":{
                        "type":"text",
                        "fielddata":true
                    },
                    "time_written":{
                        "type":"text",
                        "fielddata":true
                    },
                    "translated_text":{
                        "type":"text",
                        "fielddata":true
                    }
                }
            }
        }
    }
}

结果示例：

{
    "took":1,
    "timed_out":false,
    "_shards":{
        "total":5,
        "successful":5,
        "skipped":0,
        "failed":0},
    "hits":{
        "total":1,
        "max_score":1.0,
        "hits":[{
            "_index":"textobject-index",
            "_type":"doc",
            "_id":"10",
            "_score":1.0,
            "_source":{
                "main_text":"some long text",
                "time_written":"2010-10-12"
            }
        }]
    }
}