Elasticsearch权威指南里的聚合分析报错: Text fields are not optimised for operations that require per-document field data like aggregations and sorting。

GET /my_index/_search
{"size": 0,"aggs": {"distinct_colors": {"cardinality": {"field": "interests"}}}
}GET /my_index/_search
{"size": 0,"aggs": {"distinct_colors": {"cardinality": {"field": "age"}}}
}

在interests上进行聚合会报错，而age没问题。

  "error" : {"root_cause" : [{"type" : "illegal_argument_exception","reason" : "Text fields are not optimised for operations that require per-document field data like aggregations and sorting, so these operations are disabled by default. Please use a keyword field instead. Alternatively, set fielddata=true on [xxxx] in order to load field data by uninverting the inverted index. Note that this can use significant memory."}],"type" : "search_phase_execution_exception","reason" : "all shards failed","phase" : "query","grouped" : true,

因为interests的type是text，而age不是， text或annotated_text字段doc_values默认为false

解决方案一：  

简单理解，就是text字段作为一个整体，默认没有索引.不过text分词之后的keyword是有索引的，因而可以对interests.keyword进行聚合。

GET /my_index/_search
{"size": 0,"aggs": {"distinct_colors": {"cardinality": {"field": "interests.keyword"}}}
}增加：keyword

解决方案二：

set fielddata=true，不过不推荐

PUT employee/_mapping 
{"properties": {"interests": {"type": "text","fielddata": true}}
}