加权 #

如果你搜索“pitcher”这个词，你的结果可能既与棒球运动员有关，也与盛液体的容器有关。在棒球语境下搜索时，你可能想通过使用 must_not 子句完全排除包含“glass”或“water”的搜索结果。然而，如果你想保留这些结果但降低它们的关联度，可以使用 boosting 查询。

一个 boosting 查询返回与 positive 查询匹配的文档。在这些文档中，与 negative 查询也匹配的文档的关联度得分会降低（它们的关联度得分会乘以负的提升因子）。

参考用例 #

考虑一个包含两个文档的索引，你以如下方式索引：

PUT testindex/_doc/1
{
  "article_name": "The greatest pitcher in baseball history"
}

PUT testindex/_doc/2
{
  "article_name": "The making of a glass pitcher"
}

使用以下匹配查询来搜索包含单词“pitcher”的文档：

GET testindex/_search
{
  "query": {
    "match": {
      "article_name": "pitcher"
    }
  }
}

返回的两个文档具有相同的相关性分数：

{
  "took": 5,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": {
      "value": 2,
      "relation": "eq"
    },
    "max_score": 0.18232156,
    "hits": [
      {
        "_index": "testindex",
        "_id": "1",
        "_score": 0.18232156,
        "_source": {
          "article_name": "The greatest pitcher in baseball history"
        }
      },
      {
        "_index": "testindex",
        "_id": "2",
        "_score": 0.18232156,
        "_source": {
          "article_name": "The making of a glass pitcher"
        }
      }
    ]
  }
}

现在使用以下 boosting 查询来搜索包含单词“pitcher”的文档，但降低包含单词“glass”、“crystal”或“water”的文档的分数：

GET testindex/_search
{
  "query": {
    "boosting": {
      "positive": {
        "match": {
          "article_name": "pitcher"
        }
      },
      "negative": {
        "match": {
          "article_name": "glass crystal water"
        }
      },
      "negative_boost": 0.1
    }
  }
}

两个文档仍然会返回，但包含“glass”这个词的文档的相关性得分比之前的情况低 10 倍：

{
  "took": 13,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": {
      "value": 2,
      "relation": "eq"
    },
    "max_score": 0.18232156,
    "hits": [
      {
        "_index": "testindex",
        "_id": "1",
        "_score": 0.18232156,
        "_source": {
          "article_name": "The greatest pitcher in baseball history"
        }
      },
      {
        "_index": "testindex",
        "_id": "2",
        "_score": 0.018232157,
        "_source": {
          "article_name": "The making of a glass pitcher"
        }
      }
    ]
  }
}

参数说明 #

下表列出了 boosting 查询支持的所有顶层参数。