Elasticsearch 的 auto_generate_phrase_queries 有什么作用？

Question

在查询字符串查询的文档中，auto_generate_phrase_queries被列为参数，但唯一的描述是"defaults to false."那么这个参数到底是做什么的？

http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/query-dsl-query-string-query.html

Answer 1

这将直接匹配到 lucene 的 org.apache.lucene.queryparser.classic.QueryParserSettings#autoGeneratePhraseQueries。当分析器应用于查询字符串时，此设置允许 lucene 生成无关键字的引用短语。

Quoting:

SOLR-2015: Add a boolean attribute autoGeneratePhraseQueries to TextField. autoGeneratePhraseQueries="true" (the default) causes the query parser to generate phrase queries if multiple tokens are generated from a single non-quoted analysis string. For example WordDelimiterFilter splitting text:pdp-11 will cause the parser to generate text:"pdp 11" rather than (text:PDP OR text:11). Note that autoGeneratePhraseQueries="true" tends to not work well for non whitespace delimited languages.

其中单词分隔符用作 WordDelimiterFilter.html

需要注意的重要事项是 single non-quoted analysis string，即如果您的查询字符串未被引号括起来。如果您已经在搜索引用的短语，那么它没有任何意义。