elasticsearch - Elasticsearch 中的多字段文本和关键字字段

Question

我正在考虑从 solr 切换到 elasticsearch 并在不提供模式/映射的情况下将一堆文档编入索引，并且我之前在 solr 中设置为索引字符串的许多字段已设置为text和 keyword使用 multi-fields 的字段.

拥有 keyword 有什么好处吗？字段也作为 text字段使用 multi-fields ？在我的例子中，字段中的大多数值都是单个单词，所以我想如果将它们发送到分析器并不重要，但 es 文档似乎暗示 keyword搜索时不考虑字段或至少区别对待？

如果我搜索术语“ipad”，那么如果它在关键字字段以及其他一些文本字段中包含“ipad”与没有关键字字段的同一文档相比，文档得分会更高？如果说“ipad”仅在关键字字段中，文档是否仍然匹配？

Answer 1

为了回答我自己的问题，我创建了一个快速测试，搜索时几乎所有关键字和文本字段都是等效的，而且多字段似乎获得与其主要类型相同的分数，所以我猜第二个字段对搜索评分没有影响

奇怪的是，关键字和文本字段中的多词值得到了相同的分数，我希望关键字字段的分数更低或根本没有，但出于我的目的，这很好，所以我不打算进一步调查它.

索引创建

PUT test_index
{
    "settings" : {
        "number_of_shards" : 1
    },
    "mappings" : {
        "test_type" : {
            "properties" : {
                "multifield": {
                  "type": "text",
                  "fields": {
                     "keyword": {
                        "type": "keyword",
                        "ignore_above": 256
                     }
                  }
                },

                "keywordfield": {
                  "type": "keyword"
                },

                "textfield": {
                  "type": "text"
                }

            }
        }
    }
}

数据插入

POST /_bulk
{ "update": { "_index": "test_index", "_type": "test_type", "_id": 1 }
{ "doc" : { "multifield" : "ipad"  }, "doc_as_upsert" : true }
{ "update": { "_index": "test_index", "_type": "test_type", "_id": 2 }
{ "doc" : { "keywordfield" : "ipad"  }, "doc_as_upsert" : true }
{ "update": { "_index": "test_index", "_type": "test_type", "_id": 3 }
{ "doc" : { "keywordfield" : "a green ipad"  }, "doc_as_upsert" : true }
{ "update": { "_index": "test_index", "_type": "test_type", "_id": 4 }
{ "doc" : { "textfield" : "a yellow ipad"  }, "doc_as_upsert" : true }
{ "update": { "_index": "test_index", "_type": "test_type", "_id": 5 }
{ "doc" : { "keywordfield" : "ipad", "textfield" : "ipad"  }, "doc_as_upsert" : true }
{ "update": { "_index": "test_index", "_type": "test_type", "_id": 6 }
{ "doc" : { "keywordfield" : "unrelated", "textfield" : "hopefully this wont show up"  }, "doc_as_upsert" : true }
{ "update": { "_index": "test_index", "_type": "test_type", "_id": 7 }
{ "doc" : { "textfield" : "ipad"  }, "doc_as_upsert" : true }

结果

GET /test_index/_search?q=ipad
{
   "took": 1,
   "timed_out": false,
   "_shards": {
      "total": 1,
      "successful": 1,
      "failed": 0
   },
   "hits": {
      "total": 6,
      "max_score": 0.28122374,
      "hits": [
         {
            "_index": "test_index",
            "_type": "test_type",
            "_id": "5",
            "_score": 0.28122374,
            "_source": {
               "keywordfield": "ipad",
               "textfield": "ipad"
            }
         },
         {
            "_index": "test_index",
            "_type": "test_type",
            "_id": "1",
            "_score": 0.2734406,
            "_source": {
               "multifield": "ipad"
            }
         },
         {
            "_index": "test_index",
            "_type": "test_type",
            "_id": "2",
            "_score": 0.2734406,
            "_source": {
               "keywordfield": "ipad"
            }
         },
         {
            "_index": "test_index",
            "_type": "test_type",
            "_id": "7",
            "_score": 0.2734406,
            "_source": {
               "textfield": "ipad"
            }
         },
         {
            "_index": "test_index",
            "_type": "test_type",
            "_id": "3",
            "_score": 0.16417998,
            "_source": {
               "keywordfield": "a green ipad"
            }
         },
         {
            "_index": "test_index",
            "_type": "test_type",
            "_id": "4",
            "_score": 0.16417998,
            "_source": {
               "textfield": "a yellow ipad"
            }
         }
      ]
   }
}