Fielddata is disabled on text fields by default. Set fielddata=true on [make] in order to load

场景

• ES对text类型的字段进行聚合操作的时候, 报 Fielddata is disabled on text fields by default. Set fielddata=true on [make] 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.

分析

• 官方文档
• sort, aggregate, or access values from a script on a text field 这些行为会需要从内存中加载数据, 但是text类型的数据可能会消耗非常多内存, 另外可能会导致查询延迟, 所以默认不允许对text字段这样操作

Fielddata can consume a lot of heap space, especially when loading high cardinality text fields. Once fielddata has been loaded into the heap, it remains there for the lifetime of the segment. Also, loading fielddata is an expensive process which can cause users to experience latency hits. This is why fielddata is disabled by default.

If you try to sort, aggregate, or access values from a script on a text field, you will see this exception:Fielddata is disabled on text fields by default. Set fielddata=true on
[your_field_name] in order to load fielddata in memory by uninverting the
inverted index. Note that this can however use significant memory.

解决

PUT my_index/_mapping
{
  "properties": {
    "my_field": { 
      "type":     "text",
      "fielddata": true
    }
  }
}