Elasticsearch的检索与聚合：后过滤器post_filter_elasticsearch 聚合后过滤

1.使用场景

我们可能会想，“只过滤搜索结果，不过滤聚合结果呢？” 答案是使用 post_filter 。
它是接收一个过滤器的顶层搜索请求元素。这个过滤器在查询 之后 执行（这正是该过滤器的名字的由来：它在查询之后 post 执行）。正因为它在查询之后执行，它对查询范围没有任何影响，所以对聚合也不会有任何影响。

测试

{
  "from": 0,
  "size": 10,
  "query": {
    "bool": {
      "must": [
        {
          "bool": {
            "must": [
              {
                "multi_match": {
                  "query": "期刊",
                  "fields": [
                    "eissn^1.0",
                    "name^1.0",
                    "pissn^1.0",
                    "publisherName^1.0"
                  ],
                  "type": "phrase",
                  "operator": "OR",
                  "slop": 0,
                  "prefix_length": 0,
                  "max_expansions": 50,
                  "zero_terms_query": "NONE",
                  "auto_generate_synonyms_phrase_query": true,
                  "fuzzy_transpositions": true,
                  "boost": 1.0
                }
              }
            ],
            "adjust_pure_negative": true,
            "boost": 1.0
          }
        }
      ],
      "adjust_pure_negative": true,
      "boost": 1.0
    }
  },

  "version": true,
  "explain": false,
  "_source": {
    "includes": [
      "name",
      "eissn",
      "pissn",
      "publisherName",
      "id",
      "language",
      "subject"
    ],
    "excludes": []
  },
  "sort": [
    {
      "name.raw": {
        "order": "asc"
      }
    }
  ],
  "aggregations": {
    "language": {
      "terms": {
        "field": "language.raw",
        "size": 10,
        "min_doc_count": 1,
        "shard_min_doc_count": 0,
        "show_term_doc_count_error": false,
        "order": [
          {
            "_count": "asc"
          },
          {
            "_key": "asc"
          }
        ]
      }
    },
    "publisherName": {
      "terms": {
        "field": "publisherName.raw",
        "size": 10,
        "min_doc_count": 1,
        "shard_min_doc_count": 0,
        "show_term_doc_count_error": false,
        "order": [
          {
            "_count": "desc"
          },
          {
            "_key": "asc"
          }
        ]
      }
    }
  } 
}
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DSL查询语句目前共包含一个query查询条件和两个聚合项，检索结果如下：

原有的DSL语句增加post_filter

 "post_filter": {
    "bool": {
      "filter": [
        {
          "match_phrase": {
            "publisherName": {
              "query": "中国社科院",
              "slop": 0,
              "zero_terms_query": "NONE",
              "boost": 1.0
            }
          }
        }
      ],
      "adjust_pure_negative": true,
      "boost": 1.0
    }
  }
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检索结果如下，聚合项并未改变，检索出来的记录在执行完查询后通过post_filter又过滤了一遍