根據es官網的文件執行

GET /megacorp/employee/_search

{

  "aggs": {

    "all_interests": {

      "terms": { "field": "interests" }

    }

  }

}

這個例子時，報錯

{

  "error": {

    "root_cause": [

      {

        "type": "illegal_argument_exception",

        "reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [interests] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory."

      }

    ],

    "type": "search_phase_execution_exception",

    "reason": "all shards failed",

    "phase": "query",

    "grouped": true,

    "failed_shards": [

      {

        "shard": 0,

        "index": "megacorp",

        "node": "-Md3f007Q3G6HtdnkXoRiA",

        "reason": {

          "type": "illegal_argument_exception",

          "reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [interests] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory."

        }

      }

    ],

    "caused_by": {

      "type": "illegal_argument_exception",

      "reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [interests] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory."

    }

  },

  "status": 400

}
 

搜了一下應該是5.x後對排序，聚合這些操作用單獨的資料結構(fielddata)快取到記憶體裡了，需要單獨開啟，官方解釋在此fielddata

簡單來說就是在聚合前執行如下操作

建立mapping時將聚合欄位改為keyword型別即可