我正在尝试使用NGram在多个字段上使用ElasticSearch进行部分匹配，但是在建立索引后我将匹配0个结果。这对我来说不是很自然，而且我什至无法让NGram在一个领域工作。对我来说，这是一个充满激情的项目，我真的希望新的搜索可以部分匹配单词。我尝试使用模糊性，但它开始对不正确的匹配评分太高。
索引创建：
var nGramFilters = new List<string> { "lowercase", "asciifolding", "nGram_filter" };
Client.Indices.Create(CurrentIndexName, c => c
.Settings(st => st
.Analysis(an => an // https://stackoverflow.com/questions/38065966/token-chars-mapping-to-ngram-filter-elasticsearch-nest
.Analyzers(anz => anz
.Custom("ngram_analyzer", cc => cc
.Tokenizer("ngram_tokenizer")
.Filters(nGramFilters))
)
.Tokenizers(tz => tz
.NGram("ngram_tokenizer", td => td
.MinGram(2)
.MaxGram(20)
.TokenChars(
TokenChar.Letter,
TokenChar.Digit,
TokenChar.Punctuation,
TokenChar.Symbol
)
)
)
)
)
.Map<Package>(map => map
.AutoMap()
.Properties(p => p
.Text(t => t
.Name(n => n.Title)
.Fields(f => f
.Keyword(k => k
.Name("keyword")
.IgnoreAbove(256)
)
.Text(tt => tt
.Name("ngram")
.Analyzer("ngram_analyzer")
)
)
)
.Text(t => t
.Name(n => n.Summary)
.Fields(f => f
.Keyword(k => k
.Name("keyword")
.IgnoreAbove(256)
)
.Text(tt => tt
.Name("ngram")
.Analyzer("ngram_analyzer")
)
)
)
.Text(t => t
.Name(n => n.PestControlledBy)
.Fields(f => f
.Keyword(k => k
.Name("keyword")
.IgnoreAbove(256)
)
.Text(tt => tt
.Name("ngram")
.Analyzer("ngram_analyzer")
)
)
)
.Text(t => t
.Name(n => n.PesticideControlsThesePests)
.Fields(f => f
.Keyword(k => k
.Name("keyword")
.IgnoreAbove(256)
)
.Text(tt => tt
.Name("ngram")
.Analyzer("ngram_analyzer")
)
)
)
.Text(t => t
.Name(n => n.PesticideInstructions)
.Fields(f => f
.Keyword(k => k
.Name("keyword")
.IgnoreAbove(256)
)
.Text(tt => tt
.Name("ngram")
.Analyzer("ngram_analyzer")
)
)
)
.Text(t => t
.Name(n => n.PesticideActiveIngredients)
.Fields(f => f
.Keyword(k => k
.Name("keyword")
.IgnoreAbove(256)
)
.Text(tt => tt
.Name("ngram")
.Analyzer("ngram_analyzer")
)
)
)
.Text(t => t
.Name(n => n.PesticidesContainingThisActiveIngredient)
.Fields(f => f
.Keyword(k => k
.Name("keyword")
.IgnoreAbove(256)
)
.Text(tt => tt
.Name("ngram")
.Analyzer("ngram_analyzer")
)
)
)
.Text(t => t
.Name(n => n.PesticideSafeOn)
.Fields(f => f
.Keyword(k => k
.Name("keyword")
.IgnoreAbove(256)
)
.Text(tt => tt
.Name("ngram")
.Analyzer("ngram_analyzer")
)
)
)
.Text(t => t
.Name(n => n.PesticideNotSafeOn)
.Fields(f => f
.Keyword(k => k
.Name("keyword")
.IgnoreAbove(256)
)
.Text(tt => tt
.Name("ngram")
.Analyzer("ngram_analyzer")
)
)
)
)
)
);
查询：
var result = _client.Search<Package>(s => s
.From((form.Page - 1) * form.PageSize)
.Size(form.PageSize)
.Query(query => query
.MultiMatch(m => m
.Fields(f => f
.Field(p => p.Title.Suffix("ngram"), 1.5)
.Field(p => p.Summary.Suffix("ngram"), 1.1)
.Field(p => p.PestControlledBy.Suffix("ngram"), 1.0)
.Field(p => p.PesticideControlsThesePests.Suffix("ngram"), 1.0)
.Field(p => p.PesticideInstructions.Suffix("ngram"), 1.0)
.Field(p => p.PesticideActiveIngredients.Suffix("ngram"), 1.0)
.Field(p => p.PesticidesContainingThisActiveIngredient.Suffix("ngram"), 1.0)
.Field(p => p.PesticideSafeOn.Suffix("ngram"), 1.0)
.Field(p => p.PesticideNotSafeOn.Suffix("ngram"), 1.0)
)
.Operator(Operator.Or) // https://stackoverflow.com/questions/46139028/elasticsearch-how-to-do-a-partial-match-from-your-query
.Query(form.Query)
)
)
.Highlight(h => h
.PreTags("<strong>")
.PostTags("</strong>")
.Encoder(HighlighterEncoder.Html) //https://github.com/elastic/elasticsearch-net/issues/3091
.Fields(fs => fs
.Field(f => f.Summary.Suffix("ngram")),
fs => fs
.Field(p => p.PestControlledBy.Suffix("ngram")),
fs => fs
.Field(p => p.PesticideControlsThesePests.Suffix("ngram")),
fs => fs
.Field(p => p.PesticideInstructions.Suffix("ngram")),
fs => fs
.Field(p => p.PesticideActiveIngredients.Suffix("ngram")),
fs => fs
.Field(p => p.PesticidesContainingThisActiveIngredient.Suffix("ngram")),
fs => fs
.Field(p => p.PesticideSafeOn.Suffix("ngram")),
fs => fs
.Field(p => p.PesticideNotSafeOn.Suffix("ngram"))
.NumberOfFragments(10)
.FragmentSize(250)
)
)
);
我什至在正确的球场吗？我尝试使用默认的分析仪，但对于“猫耳朵蒲公英”和类似的东西，我没有匹配“猫蒲公英”。使用默认的分析器...整个单词都必须匹配，但是我希望部分匹配能够正常工作以获取“花瓣”和“花瓣”之类的东西。朝正确方向迈出的任何一步都值得赞赏。我对ElasticSearch和NEST完全陌生，现在只使用了一周左右。
client.Indices.Create调用无效，这有两个原因：
MinGram与MaxGram之间的差异不能大于1，因此会出现此错误Elasticsearch.Net.ElasticsearchClientException: Request failed to execute. Call: Status code 400 from: PUT /my_index1?pretty=true&error_trace=true. ServerError: Type: illegal_argument_exception Reason: "The difference between max_gram and min_gram in NGram Tokenizer must be less than or equal to: [1] but was [18]. This limit can be set by changing the [index.max_ngram_diff] index level setting."
您可以阅读有关此错误here的更多信息。
nGram_filter这样的过滤器，您需要将其更改为ngram我通过检查Elasticsearch（localhost：9200 / YOUR_INDEX_NAME / _mapping）中的索引映射发现了这些问题，在那里我发现未应用映射。第二步是查看DebugInformation必须从索引创建响应中告诉我什么
var createIndexResponse = await client.Indices.CreateAsync("my_index1", ..);
createIndexResponse.DebugInformation
希望有所帮助。