Elasticsearch : Completion suggester not working with whitespace Analyzer

Question

我是 Elastic search 的新手，我正在尝试使用 whitespace Analyzer 创建一个 Completion suggester 演示。

As per the documentation of Whitespace Analyzer, It breaks text into terms whenever it encounters a whitespace character. So my question is do it works with Completion suggester too?

So for my completion suggester prefix : "ela", I am expecting output as "Hello elastic search."

我知道一个简单的解决方案是将多字段输入添加为:

"suggest": {
         "input": ["Hello","elastic","search"]
 }

However, if this is the solution then what is meaning of using analyzer? Does analyzer make sense in completion suggester?

我的映射:

{
  "settings": {
    "analysis": {
      "analyzer": {
        "completion_analyzer": {
          "type": "custom",
          "filter": [
            "lowercase"
          ],
          "tokenizer": "whitespace"
        }
      }
    }
  },
  "mappings": {
            "my-type": {
                "properties": {
                    "mytext": {
                        "type": "text",
                        "fields": {
                            "keyword": {
                                "type": "keyword",
                                "ignore_above": 256
                            }
                        }
                    },
                    "suggest": {
                        "type": "completion",
                        "analyzer": "completion_analyzer",
                        "search_analyzer": "completion_analyzer",
                        "max_input_length": 50
                    }
                }
            }
        }
}

我的文档:

{
    "_index": "my-index",
    "_type": "my-type",
    "_id": "KTWJBGEBQk_Zl_sQdo9N",
    "_score": 1,
    "_source": {
        "mytext": "dummy text",
        "suggest": {
                 "input": "Hello elastic search."
        }
    }
}

搜索请求:

{
    "suggest": {
        "test-suggest" : {
        "prefix" :"ela", 
        "completion" : { 
            "field" : "suggest",
            "skip_duplicates": true
        }
        }
    }
}

此搜索没有返回正确的输出，但如果我使用 prefix = 'hel'，我会得到正确的输出:“Hello elastic search。”

简而言之，我想知道 whitespace Analyzer 是否与 completion suggester 一起工作？如果有办法，请给我建议。

PS:我已经在寻找这个链接，但没有找到有用的答案。

ElasticSearch completion suggester Standard Analyzer not working

What Elasticsearch Analyzer to use for this completion suggester?

我发现此链接很有用 Word-oriented completion suggester (ElasticSearch 5.x) .但是他们没有使用完成建议器。

提前致谢。

吉米

Answer 1

补全建议器无法执行全文查询，这意味着它无法根据多词字段中间的词返回建议。

来自 ElasticSearch本身:

The reason is that an FST query is not the same as a full text query. We can't find words anywhere within a phrase. Instead, we have to start at the left of the graph and move towards the right.

正如您所发现的，可以匹配字段中间的完成建议器的最佳替代方法是边缘 n-gram 过滤器。