Query DSL - 查询和过滤上下文

最新推荐文章于 2023-02-13 01:29:09 发布

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最新推荐文章于 2023-02-13 01:29:09 发布

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分类专栏： elasticsearch 文章标签： elasticsearch

原文链接：https://www.elastic.co/guide/en/elasticsearch/reference/7.5/query-filter-context.html

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Query and filter context

查询和过滤上下文

Relevance scores

Query context

查询上下文

In the query context, a query clause answers the question “How well does this document match this query clause?” Besides deciding whether or not the document matches, the query clause also calculates a relevance score in the _score meta-field.

在查询上下文中，查询子句回答这样的问题“ 此文档与该查询子句的匹配程度如何？”除了确定文档是否匹配外，查询子句还计算meta-field（元字段)_score的相关性得分。

Query context is in effect whenever a query clause is passed to a query parameter, such as the query parameter in the search API.

查询上下文在查询子句中通过query 参数设置，例如：

GET /_search
{
    "query" : {
        "term" : { "user" : "kimchy" }
    }
}

Filter context

过滤器上下文

In a filter context, a query clause answers the question “Does this document match this query clause?” The answer is a simple Yes or No — no scores are calculated. Filter context is mostly used for filtering structured data, e.g.

在过滤器上下文中，查询子句回答这样的问题“ *此文档是否与此查询子句匹配？*答案是简单的是或否-不计算分数。过滤器上下文主要用于过滤结构化数据，例如

Does this timestamp fall into the range 2015 to 2016?
Is the status field set to "published"?
timestamp是否属于2015年至2016年的范围？
*status 字段设置为"published"*吗？

Frequently used filters will be cached automatically by Elasticsearch, to speed up performance.

常用过滤器将由Elasticsearch自动缓存，以提高性能。

Filter context is in effect whenever a query clause is passed to a filter parameter, such as the filter or must_not parameters in the bool query, the filter parameter in the constant_score query, or the filter aggregation.

过滤器上下文在查询子句中通过filter 参数设置（例如 bool查询中的filter参数和must_not参数， constant_score中的filter参数，或者filter聚合）。

Example of query and filter contexts

查询和过滤器上下文示例

Below is an example of query clauses being used in query and filter context in the search API. This query will match documents where all of the following conditions are met:

以下是在searchAPI中使用查询上下文和过滤器上下文查询子句的示例。此查询将匹配满足以下所有条件的文档：

The title field contains the word search.
The content field contains the word elasticsearch.
The status field contains the exact word published.
The publish_date field contains a date from 1 Jan 2015 onwards.
该title字段包含单词search。
该content字段包含单词elasticsearch。
该status字段包含确切的单词published。
该publish_date字段包含从2015年1月1日开始的日期。

GET /_search
{
  "query": { 
    "bool": { 
      "must": [
        { "match": { "title":   "Search"        }},
        { "match": { "content": "Elasticsearch" }}
      ],
      "filter": [ 
        { "term":  { "status": "published" }},
        { "range": { "publish_date": { "gte": "2015-01-01" }}}
      ]
    }
  }
}

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	The `query` parameter indicates query context.
	The `bool` and two `match` clauses are used in query context, which means that they are used to score how well each document matches.
	The `filter` parameter indicates filter context. Its `term` and `range` clauses are used in filter context. They will filter out documents which do not match, but they will not affect the score for matching documents.

	`query`参数表示查询上下文。
	`must`下的两个`match`子句用于查询上下文，它们被用来表示每个文档匹配程度的评分。
	`filter`下的参数表示过滤器上下文。其`term`and `range`子句用于过滤器上下文。它们将过滤出不匹配的文档，但不会影响匹配文档的分数。

Scores calculated for queries in query context are represented as single precision floating point numbers; they have only 24 bits for significand’s precision. Score calculations that exceed the significand’s precision will be converted to floats with loss of precision.

在查询上下文中为查询计算的分数被表示为单精度浮点数；他们只有24位bits的有效数字的精度。超过有效位数精度的计算分数将转换为失去精度的浮点数。

Use query clauses in query context for conditions which should affect the score of matching documents (i.e. how well does the document match), and use all other query clauses in filter context.

在查询上下文中使用查询子句以应对可能影响匹配文档得分（即文档匹配程度）的条件，并在过滤器上下文中使用所有其他查询子句。