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

場景

• ES對text類型的字段進行聚合操作的時候, 報 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

• 官方文檔
• sort, aggregate, or access values from a script on a text field 這些行爲會需要從內存中加載數據, 但是text類型的數據可能會消耗非常多內存, 另外可能會導致查詢延遲, 所以默認不允許對text字段這樣操作

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.

解決

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