在Elasticsearch中對 text 類型的字段進行聚合異常Fielddata is disabled，Set fielddata=true

1.問題: 

1. 在Elasticsearch中對 text 類型的字段進行聚合，報異常:

腳本調用: 

GET /logstash-jsy/nginx-access/_search 
{ 
  "aggs": { 
    "all_interests": { 
      "terms": { "field": "geoip.city_name" } 
    } 
  } 
}
    

    java.lang.IllegalArgumentException: Fielddata is disabled on text fields by default. Set fielddata=true on [geoip.city_name] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead.
    at org.elasticsearch.index.mapper.TextFieldMapper$TextFieldType.fielddataBuilder(TextFieldMapper.java:336)

 

2. 緣由, 默認 Elasticsearch 對 text 類型的字段是不可聚合的，基本類型可聚合

 

3. 解決: 

            a. 設置   Fielddata = true 
            
PUT logstash-jsy/_mapping/nginx-access/
{
  "properties": {
    "geoip.city_name": { 
      "type":     "text",
      "fielddata": true
    }
  }
}
            
            
            b. 若是 Fielddata = true 沒法解決， 使用使用keyword
            
            
    查看你索引信息字段是不是這種多映射， req_url 字段既映射了  text , 又映射了 keyword
    
    
    "req_url": {

    "norms": false,
    "type": "text",
    "fields": {
        "keyword": {
            "type": "keyword"
        }
    }

}
若是是: 
        https://www.elastic.co/guide/en/elasticsearch/reference/5.4/fielddata.html#before-enabling-fielddata
    
    Use the my_field.keyword field for aggregations, sorting, or in scripts.
    即:  字段.keyword  
            
GET /logstash-jsy/nginx-access/_search 
{ 
  "aggs": { 
    "all_interests": { 
      "terms": { "field": "geoip.city_name.keyword" } 
    } 
  } 
}

TermsAggregationBuilder teamAgg = AggregationBuilders.terms("cityName_count")
                    .field("geoip.country_name.keyword").size(15);
searchResponse = elasticsearchConfig.getObject().prepareSearch(EsConstant.INDEX_NAME)
                    .setTypes(EsConstant.TYPE_NAME).setQuery(null).addAggregation(teamAgg).setSize(0).execute()
                    .actionGet();
            
            
            c. 若是還沒法解決
            
                http://www.cnblogs.com/Creator/p/3722408.html

                https://elasticsearch.cn/question/2031?notification_id=14626&comment_unfold=question