Elasticsearch嵌套查询无法处理多个MUST条件问题排查

环境与索引映射 #

使用Elasticsearch 6.5版本，创建的hotel类型索引映射如下：

{"hotel": {"mappings": {"hotel": {"properties": {"hotelAmenities": {"type": "nested","properties": {"enabled": {"type": "boolean"},"featured": {"type": "boolean"},"key": {"type": "text","fields": {"keyword": {"type": "keyword","ignore_above": 256}}},"name": {"type": "text","fields": {"keyword": {"type": "keyword","ignore_above": 256}}}}},"hotelStatus": {"type": "text","fields": {"keyword": {"type": "keyword","ignore_above": 256}}},"name": {"type": "text","fields": {"verbatim": {"type": "keyword"}},"analyzer": "english"}}}}}

示例文档 #

{"name": "Hotel with amenities","hotelStatus": "BOOKABLE","hotelAmenities": [{"key": "POOL","name": "Pool","enabled": true,"featured": true},{"key": "LAUNDRY","name": "Laundry","enabled": true,"featured": true}]}

问题现象 #

意图实现酒店同时具备POOL和LAUNDRY设施的AND逻辑，但仅单个嵌套字段查询能返回结果，多个MUST条件并存时无法找到匹配文档。

以下是两种尝试的查询写法：

第一种写法 #

{"from": 0,"size": 200,"query": {"bool": {"must": [{"nested": {"query": {"bool": {"must": [{"match": {"hotelAmenities.name": "laundry"}},{"match": {"hotelAmenities.name": "pool"}}],"adjust_pure_negative": true,"boost": 1.0}},"path": "hotelAmenities","ignore_unmapped": false,"score_mode": "max","boost": 1.0}}],"must_not": [{"match": {"hotelStatus": {"query": "DECOMMISSIONED","operator": "OR","prefix_length": 0,"max_expansions": 50,"fuzzy_transpositions": true,"lenient": false,"zero_terms_query": "NONE","auto_generate_synonyms_phrase_query": true,"boost": 1.0}}}]},"adjust_pure_negative": true,"boost": 1.0}},"post_filter": {"geo_distance": {...}},"version": true}

第二种写法 #

{"from": 0,"size": 200,"query": {"bool": {"must": [{"nested": {"query": {"bool": {"must": [{"match": {"hotelAmenities.name": {"query": "laundry","operator": "OR","prefix_length": 0,"max_expansions": 50,"fuzzy_transpositions": true,"lenient": false,"zero_terms_query": "NONE","auto_generate_synonyms_phrase_query": true,"boost": 1.0}}}},{"match": {"hotelAmenities.name": {"query": "pool","operator": "OR","prefix_length": 0,"max_expansions": 50,"fuzzy_transpositions": true,"lenient": false,"zero_terms_query": "NONE","auto_generate_synonyms_phrase_query": true,"boost": 1.0}}}}],"adjust_pure_negative": true,"boost": 1.0}},"path": "hotelAmenities","ignore_unmapped": false,"score_mode": "max","boost": 1.0}}],"must_not": [{"match": {"hotelStatus": {"query": "DECOMMISSIONED","operator": "OR","prefix_length": 0,"max_expansions": 50,"fuzzy_transpositions": true,"lenient": false,"zero_terms_query": "NONE","auto_generate_synonyms_phrase_query": true,"boost": 1.0}}}]},"adjust_pure_negative": true,"boost": 1.0}},"post_filter": {"geo_distance": {...}},"version": true}

问题原因 #

当前写法的核心错误是：在同一个嵌套查询内部用must同时匹配两个hotelAmenities.name条件，这会要求文档中存在单个嵌套对象同时满足name=laundry和name=pool，但示例文档里这两个设施是两个独立的嵌套对象，自然无法匹配。

正确查询写法 #

需要为每个设施条件单独创建一个nested查询，将它们放在外层bool的must数组中，这样Elasticsearch会检查文档中是否分别存在匹配laundry和pool的嵌套对象，从而实现AND逻辑：

{
  "from": 0,
  "size": 200,
  "query": {
    "bool": {
      "must": [
        {
          "nested": {
            "query": {
              "match": {
                "hotelAmenities.name": "laundry"
              }
            },
            "path": "hotelAmenities",
            "score_mode": "max"
          }
        },
        {
          "nested": {
            "query": {
              "match": {
                "hotelAmenities.name": "pool"
              }
            },
            "path": "hotelAmenities",
            "score_mode": "max"
          }
        }
      ],
      "must_not": [
        {
          "match": {
            "hotelStatus": "DECOMMISSIONED"
          }
        }
      ]
    }
  },
  "post_filter": {"geo_distance": {...}},
  "version": true
}

内容的提问来源于stack exchange，提问作者mvd