深入理解ElasticSearch关键词

• Relevance

  Full-text queries find all documents that match the query string and return them sorted by relevance - how good a match they are for your search terms.

  By default, Elasticsearch sorts matching search results by relevance score, which measures how well each document mathces a query.

• Query DSL

  《理解DSL||AST||query clauses||X-Pack||JDBC||ODBC》

  You can access all kinds of search capabilities using Elasticsearch’s omprehensive JSON-style query language (Query DSL).

  Elasticsearch provides a full Query DSL (Domain Specific Language) based on JSON to define queries.

  Think of the Query DSL as an AST (Abstract Syntax Tree) of queries, consisting of two types of clauses:

  • Leaf query clauses
  • Compouned query clauses

• SQL access

  Elasticsearch SQL aims to provide a powerful yet lightweight SQL interface to Elasticsearch.

  Elasticsearch SQL is an X-Pack component that allows SQL-like queries to be executed in realtime against Elasticsearch.