搜索推荐,search as you type,搜索提示,解释一下什么意思
hello w --> 点击搜索(下面的结果都给你推荐出来)
hello world
hello we
hello win
hello wind
hello dog
hello cat
hello w -->
hello world
hello we
hello win
hello wind
搜索推荐的功能
添加数据
PUT /my_index/my_type/1 { "title":"hello world" } PUT /my_index/my_type/2 { "title":"hello we" } PUT /my_index/my_type/3 { "title":"hello win" } PUT /my_index/my_type/4 { "title":"hello wind" } |
百度 --> elas 接下来后面的都会提示出来--> elasticsearch --> elasticsearch权威指南
搜索
GET /my_index/my_type/_search { "query": { "match_phrase_prefix": { "title": "hello w" } } } GET /my_index/my_type/_search { "query": { "match_phrase_prefix": { "title": { "query": "hello w", "slop":10, "max_expansions": 10 } } } } 结果: { "took": 4, "timed_out": false, "_shards": { "total": 5, "successful": 5, "failed": 0 }, "hits": { "total": 4, "max_score": 1.4074042, "hits": [ { "_index": "my_index", "_type": "my_type", "_id": "2", "_score": 1.4074042, "_source": { "title": "hello we" } }, { "_index": "my_index", "_type": "my_type", "_id": "4", "_score": 1.4074042, "_source": { "title": "hello wind" } }, { "_index": "my_index", "_type": "my_type", "_id": "1", "_score": 0.51623213, "_source": { "title": "hello world" } }, { "_index": "my_index", "_type": "my_type", "_id": "3", "_score": 0.51623213, "_source": { "title": "hello win" } } ] } } |
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原理跟match_phrase类似,唯一的区别,就是把最后一个term作为前缀去搜索
hello就是去进行match,搜索对应的doc
w,会作为前缀,去扫描整个倒排索引,找到所有w开头的doc
然后找到所有doc中,即包含hello,又包含w开头的字符的doc
根据你的slop去计算,看在slop范围内,能不能让hello w,正好跟doc中的hello和w开头的单词的position相匹配
也可以指定slop,但是只有最后一个term会作为前缀
max_expansions:指定prefix最多匹配多少个term,超过这个数量就不继续匹配了,限定性能
默认情况下,前缀要扫描所有的倒排索引中的term,去查找w打头的单词,但是这样性能太差。可以用max_expansions限定,w前缀最多匹配多少个term,就不再继续搜索倒排索引了。
尽量不要用,因为,最后一个前缀始终要去扫描大量的索引,性能可能会很差
搜索的时候,搜索推荐的功能,所以这个就叫做search-time 搜索推荐