搜索查询elasticsearch with ngram始终返回0个结果

我用Nest和ElasticSearch一起工作。我尝试将所有字符串字段拆分为标记。同时对托基尼尼茨使用ngram。但是,当提示查询时,我总是得到0个结果。

我的类使用api。

public class Elasticsearch
{
    string index = "video-materials";
    ElasticClient client;
    public Elasticsearch()
    {
        var settings = new ConnectionSettings(new Uri("http://localhost:9200"));
        client = new ElasticClient(settings);
        if (client.IndexExists(index).Exists)
        {
            client.DeleteIndex(index);
        }
        var nGramFilters = new List<string> { "lowercase", "asciifolding", "nGram_filter" };

        var resp = client.CreateIndex(index, c => c
             .Mappings(m => m
                .Map<ElasticVideoMaterial>(mm => mm
                    .AutoMap()
                    .Properties(p => p
                        .Text(t => t
                            .Name(n => n.OriginalTitle)
                            .Fields(f => f
                                .Keyword(k => k
                                    .Name("keyword")
                                    .IgnoreAbove(256)
                                )
                                .Text(tt => tt
                                    .Name("ngram")
                                    .Analyzer("ngram_analyzer")
                                )
                            )
                        )
                    )
                )
            )
            .Settings(s => s
                .Analysis(a => a
                    .Analyzers(anz => anz
                        .Custom("ngram_analyzer", cc => cc
                            .Filters(nGramFilters)
                            .Tokenizer("ngram_tokenizer")))
                    .Tokenizers(tz => tz
                        .NGram("ngram_tokenizer", td => td
                            .MinGram(3)
                            .MaxGram(3)
                            .TokenChars(TokenChar.Letter, TokenChar.Digit)
                        )
                    )
                )
            )
        );
    }
    public void Index(IEnumerable<ElasticVideoMaterial> models)
    {
        foreach(var model in models)
        {
            client.Index(model,i=>i.Index(index));
        }
    }
    public void Search(string query)
    {
        var resp = client.Search<ElasticVideoMaterial>(i => i
                                                        .Query(q => q
                                                            .Match(m => m
                                                                .Field(f => f.OriginalTitle.Suffix("ngram"))
                                                                .Query("Hob")
                                                            )
                                                        )
                                                        .Index(index)
                                                    ).Documents.ToList();
    }
}

我总是再次创建索引,然后索引对象列表。 为此,请使用index()方法。 这是我的索引类。

public class ElasticVideoMaterial
{
    public int ID { get; set; }
    public string Title { get; set; }
    public string OriginalTitle { get; set; }
    public float? KinopoiskRating { get; set; }
    public float? Imdb { get; set; }
    public int Duration { get; set; }
    public List<string> GenreTitles { get; set; }
    public List<string> CountryNames { get; set; }
    public DateTime? ReleaseDate { get; set; }
    public List<string> TranslationTitles { get; set; }
    public List<string> FilmMakerNames { get; set; }
    public List<string> ActorNames { get; set; }
    public List<string> ThemeNames { get; set; }
    public CompletionField Suggest { get; set; }
}

但是,当我尝试使用search()方法获得结果时,得到的结果是0。 (写过《霍比特人》之后,我希望能收到名字里有霍比特人的电影)