尽管查询正确，ElasticSearch仍未返回任何结果

Question

我在elasticsearch中创建了一个名为filebeat的索引。日志数据由elasticbeat代理在elasticsearch中发送。 我想根据名为value_of_type的特定列/字段过滤结果。使用PHP API：

$json =
    '{
        "query" : {
            "bool" : {
                "filter": [
                    {
                        "term" : 
                        {
                            "value_of_type" : "sound"
                        }
                    }
                ]
            }
        }
    }';

但是它返回0结果。 {"took":4,"timed_out":false,"_shards":{"total":5,"successful":5,"failed":0},"hits":{"total":0,"max_score":null,"hits":[]}}

在浏览器中点击myurl:9200/filebeat的结果如下所示：

{
    "filebeat": {
        "aliases": {},
        "mappings": {
            "doc": {
                "properties": {
                    "@timestamp": {
                        "type": "date"
                    },
                    "beat": {
                        "properties": {
                            "hostname": {
                                "type": "text",
                                "fields": {
                                    "keyword": {
                                        "type": "keyword",
                                        "ignore_above": 256
                                    }
                                }
                            },
                            "name": {
                                "type": "text",
                                "fields": {
                                    "keyword": {
                                        "type": "keyword",
                                        "ignore_above": 256
                                    }
                                }
                            },
                            "version": {
                                "type": "text",
                                "fields": {
                                    "keyword": {
                                        "type": "keyword",
                                        "ignore_above": 256
                                    }
                                }
                            }
                        }
                    },
                    "fields": {
                        "properties": {
                            "node": {
                                "type": "text",
                                "fields": {
                                    "keyword": {
                                        "type": "keyword",
                                        "ignore_above": 256
                                    }
                                }
                            },
                            "value_of_type": {
                                "type": "text",
                                "fields": {
                                    "keyword": {
                                        "type": "keyword",
                                        "ignore_above": 256
                                    }
                                }
                            }
                        }
                    },
                    "input_type": {
                        "type": "text",
                        "fields": {
                            "keyword": {
                                "type": "keyword",
                                "ignore_above": 256
                            }
                        }
                    },
                    "message": {
                        "type": "text",
                        "fields": {
                            "keyword": {
                                "type": "keyword",
                                "ignore_above": 256
                            }
                        }
                    },
                    "offset": {
                        "type": "long"
                    },
                    "source": {
                        "type": "text",
                        "fields": {
                            "keyword": {
                                "type": "keyword",
                                "ignore_above": 256
                            }
                        }
                    },
                    "type": {
                        "type": "text",
                        "fields": {
                            "keyword": {
                                "type": "keyword",
                                "ignore_above": 256
                            }
                        }
                    }
                }
            }
        },
        "settings": {
            "index": {
                "creation_date": "1494116541083",
                "number_of_shards": "5",
                "number_of_replicas": "1",
                "uuid": "IdhWgIqiQ-GNrZK3AvCP9g",
                "version": {
                    "created": "5020199"
                },
                "provided_name": "filebeat"
            }
        }
    }
}