前言

使用AggregationBuilders.terms("name").field("field")做分组统计：

@Test
public void getData() {
    // 根据action分组统计总数
    AggregationBuilder actionAggregation = AggregationBuilders.terms("actionCount").field("action");
    
    // cardinality相当于去重计算
    CardinalityAggregationBuilder uniqueUser = AggregationBuilders.cardinality("uniqueUser").field("userid");
    actionAggregation.subAggregation(uniqueUser);
    // 创建查询请求实例
    SearchRequest searchRequest = new SearchRequest("test-index");
    searchRequest.source(SearchSourceBuilder.searchSource().aggregation(actionAggregation));
    try {
        // 使用RestHighLevelClient发送查询请求
        SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        long totalHits = searchResponse.getHits().totalHits;
        log.info("从es命中的总数： {}", totalHits);

        Terms actionTerms = searchResponse.getAggregations().get("actionCount");
        for (Terms.Bucket bucket : actionTerms.getBuckets()) {
            String action = bucket.getKeyAsString();
            log.info("bucket key: {}", action);
            long docCount = bucket.getDocCount();
            log.info("bucket doc count: {}", docCount);
            Cardinality uniqueUser1 = bucket.getAggregations().get("uniqueUser");
            long value = uniqueUser1.getValue();
            log.info("distinct doc count: {}", value);
        }
    } catch (IOException e) {
        e.printStackTrace();
        log.error("从es统计数据失败: {}", e.getMessage());
    }
}
 

报错信息如下

ElasticsearchStatusException[Elasticsearch exception [type=search_phase_execution_exception, reason=all shards failed]
]; nested: ElasticsearchException[Elasticsearch exception [type=illegal_argument_exception, reason=Fielddata is disabled on text fields by default. Set fielddata=true on [deviceid] 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.]]; nested: ElasticsearchException[Elasticsearch exception [type=illegal_argument_exception, reason=Fielddata is disabled on text fields by default. Set fielddata=true on [userid] 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.rest.BytesRestResponse.errorFromXContent(BytesRestResponse.java:177)
    at org.elasticsearch.client.RestHighLevelClient.parseEntity(RestHighLevelClient.java:2053)
    at org.elasticsearch.client.RestHighLevelClient.parseResponseException(RestHighLevelClient.java:2030)
    at org.elasticsearch.client.RestHighLevelClient.internalPerformRequest(RestHighLevelClient.java:1777)
    at org.elasticsearch.client.RestHighLevelClient.performRequest(RestHighLevelClient.java:1734)
    at org.elasticsearch.client.RestHighLevelClient.performRequestAndParseEntity(RestHighLevelClient.java:1696)
    at org.elasticsearch.client.RestHighLevelClient.search(RestHighLevelClient.java:1092)
Caused by: ElasticsearchException[Elasticsearch exception [type=illegal_argument_exception, reason=Fielddata is disabled on text fields by default. Set fielddata=true on [deviceid] 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.]]; nested: ElasticsearchException[Elasticsearch exception [type=illegal_argument_exception, reason=Fielddata is disabled on text fields by default. Set fielddata=true on [deviceid] 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.ElasticsearchException.innerFromXContent(ElasticsearchException.java:509)
    at org.elasticsearch.ElasticsearchException.fromXContent(ElasticsearchException.java:420)
    at org.elasticsearch.ElasticsearchException.innerFromXContent(ElasticsearchException.java:450)
    at org.elasticsearch.ElasticsearchException.failureFromXContent(ElasticsearchException.java:616)
    at org.elasticsearch.rest.BytesRestResponse.errorFromXContent(BytesRestResponse.java:169)

从报错信息Caused by: ElasticsearchException[Elasticsearch exception [type=illegal_argument_exception, reason=Fielddata is disabled on text fields by default. Set fielddata=true on [userid] 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.]];中可以看出：在分组统计时，默认情况下text类型的Fielddata是被禁用的，可以在字段上面设置fielddata = true，通过取消倒排索引把fielddata加载到内存，但是这个可能会使用大量的内存，应该使用keyword类型来替代。

简单的说， 在elasticsearch中对text类型的字段进行聚合、排序时，会产生上面的错误

解决方法一：把要聚合的字段加上".keyword"就可以了

我们可以用fieldname.keyword进行聚合，排序，代码修改为如下：

// 去重聚合
AggregationBuilders.cardinality("uniqueUser").field("userid.keyword");

解决方法二：设置字段的"fielddata=true"(不推荐，这样可能会使用大量的内存)

使用如下的命令设置：

PUT /test-index/_mapping/doc
{
  "properties": {
    "userid": { 
      "type": "text",
      "fielddata": true
    }
  }
}

设置成功返回：

{
  "acknowledged" : true
}

参考文章
elasticsearch text字段排序报错解决