基于前缀和自定义标记器的Elasticsearch自动建议

Question

"nGram_filter": {
          "type": "nGram",
          "min_gram": 3,
          "max_gram": 10,
          "token_chars": [
            "letter",
            "digit",
            "punctuation",
            "symbol"
          ]
        }

"nGram_analyzer": {
          "type": "custom",
          "tokenizer": "whitespace",
          "filter": [
            "lowercase",
            "asciifolding",
            "nGram_filter"
          ]
        }

但是我需要添加另一个特性--我需要启用前缀过滤器。例如：当我搜索test_table(10个字符）时，我能够得到结果，因为最大n-gram是10，但是当我尝试test_table_for时，它返回零结果，因为记录test_table_for analyzers没有这个标记。

我怎样才能添加一个基于前缀的过滤器也为现有的n-gram分析器？就像我应该能够得到匹配的结果最多10个字符时搜索（目前工作），而且我应该能够建议什么时候搜索字符串匹配记录从开始以及。

Answer 1

这在单个分析器中是不可能的，您必须创建另一个字段，在该字段中可以创建用于prefix搜索的edge_ngram标记，添加索引映射，显示其中也包括您当前的分析器。

索引映射

{
    "settings": {
        "analysis": {
            "filter": {
                "autocomplete_filter": {
                    "type": "edge_ngram",
                    "min_gram": 1,
                    "max_gram": 30
                },
                "nGram_filter": {
                    "type": "nGram",
                    "min_gram": 3,
                    "max_gram": 10,
                    "token_chars": [
                        "letter",
                        "digit",
                        "punctuation",
                        "symbol"
                    ]
                }
            },
            "analyzer": {
                "prefixanalyzer": {
                    "type": "custom",
                    "tokenizer": "standard",
                    "filter": [
                        "lowercase",
                        "autocomplete_filter"
                    ]
                },
                "ngramanalyzer": {
                    "type": "custom",
                    "tokenizer": "standard",
                    "filter": [
                        "lowercase",
                        "nGram_filter"
                    ]
                }
            }
        },
        "index.max_ngram_diff" : 30
    },
    "mappings": {
        "properties": {
            "title_prefix": {
                "type": "text",
                "analyzer": "prefixanalyzer",
                "search_analyzer": "standard"
            },
            "title" :{
                "type": "text",
                "analyzer": "ngramanalyzer",
                "search_analyzer": "standard"
            }
        }
    }
}

现在可以使用useanalyseAPI来确认前缀标记：

{
    "analyzer": "prefixanalyzer",
    "text" : "test_table_for analyzers"
}

{"tokens":[{"token":"t","start_offset":0,"end_offset":14,"type":"<ALPHANUM>","position":0},{"token":"te","start_offset":0,"end_offset":14,"type":"<ALPHANUM>","position":0},{"token":"tes","start_offset":0,"end_offset":14,"type":"<ALPHANUM>","position":0},{"token":"test","start_offset":0,"end_offset":14,"type":"<ALPHANUM>","position":0},{"token":"test_","start_offset":0,"end_offset":14,"type":"<ALPHANUM>","position":0},{"token":"test_t","start_offset":0,"end_offset":14,"type":"<ALPHANUM>","position":0},{"token":"test_ta","start_offset":0,"end_offset":14,"type":"<ALPHANUM>","position":0},{"token":"test_tab","start_offset":0,"end_offset":14,"type":"<ALPHANUM>","position":0},{"token":"test_tabl","start_offset":0,"end_offset":14,"type":"<ALPHANUM>","position":0},{"token":"test_table","start_offset":0,"end_offset":14,"type":"<ALPHANUM>","position":0},{"token":"test_table_","start_offset":0,"end_offset":14,"type":"<ALPHANUM>","position":0},{"token":"test_table_f","start_offset":0,"end_offset":14,"type":"<ALPHANUM>","position":0},{"token":"test_table_fo","start_offset":0,"end_offset":14,"type":"<ALPHANUM>","position":0},{"token":"test_table_for","start_offset":0,"end_offset":14,"type":"<ALPHANUM>","position":0},{"token":"a","start_offset":15,"end_offset":24,"type":"<ALPHANUM>","position":1},{"token":"an","start_offset":15,"end_offset":24,"type":"<ALPHANUM>","position":1},{"token":"ana","start_offset":15,"end_offset":24,"type":"<ALPHANUM>","position":1},{"token":"anal","start_offset":15,"end_offset":24,"type":"<ALPHANUM>","position":1},{"token":"analy","start_offset":15,"end_offset":24,"type":"<ALPHANUM>","position":1},{"token":"analyz","start_offset":15,"end_offset":24,"type":"<ALPHANUM>","position":1},{"token":"analyze","start_offset":15,"end_offset":24,"type":"<ALPHANUM>","position":1},{"token":"analyzer","start_offset":15,"end_offset":24,"type":"<ALPHANUM>","position":1},{"token":"analyzers","start_offset":15,"end_offset":24,"type":"<ALPHANUM>","position":1}]}

{
    "query": {
        "multi_match": {
            "query": "test_table_for",
            "fields": [
                "title",
                "title_prefix"
            ]
        }
    }
}

 "hits": [
            {
                "_index": "so_63981157",
                "_type": "_doc",
                "_id": "1",
                "_score": 0.45920232,
                "_source": {
                    "title_prefix": "test_table_for analyzers",
                    "title": "test_table_for analyzers"
                }
            }
        ]