elasticsearch 按一个字母搜索

Question

我有一个这样设置的索引:

settings: {
index.analysis.analyzer.eng_search_analyzer.filter.0: lowercase
index.analysis.analyzer.eng_search_analyzer.filter.1: icu_folding
index.analysis.analyzer.eng_search_analyzer.char_filter.0: html_strip
index.analysis.filter.eng_ngram_filter.type: nGram
index.analysis.filter.eng_ngram_filter.min_gram: 1
index.analysis.analyzer.eng_search_analyzer.tokenizer: whitespace
index.analysis.analyzer.eng_search_analyzer.filter.2: icu_normalizer
index.analysis.analyzer.eng_index_analyzer.filter.1: eng_ngram_filter
index.analysis.analyzer.eng_index_analyzer.filter.0: lowercase
index.number_of_shards: 2
index.analysis.filter.eng_ngram_filter.token_chars.1: digit
index.analysis.filter.eng_ngram_filter.token_chars.0: letter
index.analysis.filter.eng_ngram_filter.token_chars.3: symbol
index.analysis.filter.eng_ngram_filter.token_chars.2: punctuation
index.analysis.analyzer.eng_index_analyzer.type: custom
index.analysis.analyzer.eng_index_analyzer.char_filter.0: html_strip
index.analysis.analyzer.eng_index_analyzer.filter.3: icu_normalizer
index.analysis.filter.eng_ngram_filter.max_gram: 20
index.analysis.analyzer.eng_index_analyzer.filter.2: icu_folding
index.number_of_replicas: 1
index.analysis.analyzer.eng_index_analyzer.tokenizer: whitespace
index.analysis.analyzer.eng_search_analyzer.type: custom
index.version.created: 900799
index.uuid: -O-iV6ZIQh6gk1204Ec1ig
}

并且几个重要字段的字段映射是这样设置的:

{
  "name": {
    "type": "multi_field",
    "fields": {
      "name": {
        "type": "string",
        "index": "not_analyzed",
        "omit_norms": "true",
        "index_options": "docs",
        "null_value": ""
      },
      "analyzed": {
        "type": "string",
        "index_analyzer": "eng_index_analyzer",
        "search_analyzer": "eng_search_analyzer",
        "null_value": "",
        "include_in_all": "false"
      }
    }
  }
}

当我查询 name.analyzed 字段时，它适用于至少包含两个字符的任何内容。例如，查询“Ra”将在名称字段中找到带有“Rafael”的文档。但是，当我查询“R”或“Rafael S”时，它没有返回任何结果。应该注意的是，在我们的查询中，空格被处理为“AND”运算符而不是“OR”，因此查询词基本上被处理为 - “name contains [search term]”。

如何配置字段或分析器以便搜索单个字母？

Answer 1

如果没有看到查询就很难说，但是根据 discussion on the elastic forum 的说法，如果您使用的是 match_phrase_prefix 查询，您可能会通过增加查询的“max_expansions”属性取得一些成功，尽管它会降低速度。

“max_expansions”:10000

该线程中的另一个潜在解决方案是将 operator 或 default_operator 设置为 "and"(我想您已经完成了)。