elasticsearch - 如何在查询时而不是在 Elasticsearch 中的索引时应用同义词

Question

根据 the elasticsearch reference documentation , 可以:

Expansion can be applied either at index time or at query time. Each has advantages (⬆)︎ and disadvantages (⬇)︎. When to use which comes down to performance versus flexibility.

优点和缺点都很有意义，对于我的特定用途，我想在查询时使用同义词。我的用例是，我想让系统中的管理员用户管理这些同义词，而不必在更新时重新索引所有内容。另外，我想在不关闭和重新打开索引的情况下执行此操作。

我认为这是可能的主要原因是这个优势:

(⬆)︎ Synonym rules can be updated without reindexing documents.

但是，我找不到任何描述如何在查询时而非索引时应用同义词的文档。

使用一个具体示例，如果我执行以下操作(从 the reference 中窃取并稍作修改的示例)，这似乎会在索引时应用同义词:

/* NOTE: This was all run against elasticsearch 1.5 (if that matters; documentation is identical in 2.x) */

// Create our synonyms filter and analyzer on the index
PUT my_synonyms_test
{
  "settings": {
    "analysis": {
      "filter": {
        "my_synonym_filter": {
          "type": "synonym",
          "synonyms": [
            "queen,monarch"
          ]
        }
      },
      "analyzer": {
        "my_synonyms": {
          "tokenizer": "standard",
          "filter": [
            "lowercase",
            "my_synonym_filter"
          ]
        }
      }
    }
  }
}

// Create a mapping that uses this analyzer
PUT my_synonyms_test/rulers/_mapping
{
  "properties": {
    "name": {
      "type": "string"
    },
    "title": {
      "type": "string",
      "analyzer": "my_synonyms"
    }
  }
}

// Some data
PUT my_synonyms_test/rulers/1
{
  "name": "Elizabeth II",
  "title": "Queen"
}

// A query which utilises the synonyms
GET my_synonyms_test/rulers/_search
{
  "query": {
    "match": {
      "title": "monarch"
    }
  }
}

// And we get our expected result back:
{
   "took": 42,
   "timed_out": false,
   "_shards": {
      "total": 1,
      "successful": 1,
      "failed": 0
   },
   "hits": {
      "total": 1,
      "max_score": 1.4142135,
      "hits": [
         {
            "_index": "my_synonyms_test",
            "_type": "rulers",
            "_id": "1",
            "_score": 1.4142135,
            "_source": {
               "name": "Elizabeth II",
               "title": "Queen"
            }
         }
      ]
   }
}

所以我的问题是:如何修改上面的示例，以便在查询时 使用同义词？

或者我完全找错了树，你能指点我别的地方吗？我看过类似问题的答案中提到的插件，如 https://stackoverflow.com/a/34210587/2240218和 https://stackoverflow.com/a/18481495/2240218但它们似乎都有几年历史且无人维护，所以我宁愿避免使用这些。

Answer 1

只需在映射中使用 search_analyzer 而不是 analyzer，您的同义词分析器将仅在搜索时使用

PUT my_synonyms_test/rulers/_mapping
{
  "properties": {
    "name": {
      "type": "string"
    },
    "title": {
      "type": "string",
      "search_analyzer": "my_synonyms"       <--- change this
    }
  }
}