Elasticsearch关键字以及小写和聚合 [英] Elasticsearch keyword and lowercase and aggregation

问题描述

我以前用映射关键字存储了一些字段。但是，它们是区分大小写的。

I have previously stored some fields with the mapping "keyword". But, they are case senstive.

要解决此问题，可以使用分析仪，例如

To solve this, it is possible to use an analyzer, such as

{
  "index": {
    "analysis": {
      "analyzer": {
        "keyword_lowercase": {
          "tokenizer": "keyword",
          "filter": [
            "lowercase"
          ]
        }
      }
    }
  }
}

有映射

{
  "properties": {
    "field": {
      "type": "string",
      "analyzer": "keyword_lowercase"
    }
  }
}

按条件聚合不起作用。

原因：java.lang.IllegalArgumentException：默认情况下，文本字段的字段数据处于禁用状态。在[a]上设置fielddata = true，以通过反转取反的索引将字段数据加载到内存中。但是请注意，这可能会占用大量内存。

Caused by: java.lang.IllegalArgumentException: Fielddata is disabled on text fields by default. Set fielddata=true on [a] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory.

它适用于映射type = keyword，但是type = keyword不允许分析器

It works on mapping type=keyword, but type=keyword does not allow analyzer it seems.

如何将其索引为小写关键字，但仍然可以在不设置fielddata = true的情况下使用聚合？

推荐答案

如果您使用的是ES 5.2或更高版本，则现在可以使用 规范化器 s for 关键字字段。只需像这样声明索引设置和映射就可以了

If you're using ES 5.2 or above, you can now leverage normalizers for keyword fields. Simply declare your index settings and mappings like this and you're good to go

PUT index
{
  "settings": {
    "analysis": {
      "normalizer": {
        "keyword_lowercase": {
          "type": "custom",
          "filter": ["lowercase"]
        }
      }
    }
  },
  "mappings": {
    "type": {
      "properties": {
        "field": {
          "type": "keyword",
          "normalizer": "keyword_lowercase"
        }
      }
    }
  }
}

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