使用 NEST 7 进行 ElasticSearch 排序答案

【问题标题】：ElasticSearch Sorting using NEST 7使用 NEST 7 进行 ElasticSearch 排序
【发布时间】：2020-09-19 11:43:20
【问题描述】：

我正在使用 ElarsticSearch 7.7 和 NEST 7.7，我正在尝试使用排序功能。但我遇到了一个错误，

我收到一条错误消息， “类型：非法参数异常原因：“文本字段没有针对需要按文档字段数据的操作进行优化，例如聚合和排序，因此默认情况下禁用这些操作。请改用关键字字段。或者，在 [name] 上设置 fielddata=true 以通过反转倒排索引来加载字段数据。请注意，这可能会占用大量内存。” 由：“类型：非法参数异常原因：“文本字段未针对需要按文档字段数据的操作（如聚合和排序）进行优化，因此默认情况下禁用这些操作。请使用关键字字段代替。或者，在 [name] 上设置 fielddata=true 以通过反转反转来加载字段数据

这是我下面的代码

public SearchResult Search(string searchQuery, int storeId, int pageNumber = 1, int pageSize = 10, IList<SearchFilter> requestFilter = null, decimal? priceFrom = null, decimal? priceTo = null, string sortBy = null)
    {
        var queryContainer = new QueryContainer(); 
        var multiMatch = new QueryStringQuery
        {
            Fields = Infer.Field<ElasticIndexGroupProduct>(p => p.Name)
                     .And(Infer.Field<ElasticIndexGroupProduct>(p => p.CategoryName))
                     .And(Infer.Field<ElasticIndexGroupProduct>(p => p.VendorName))                        
                     .And(Infer.Field<ElasticIndexGroupProduct>(p => p.AssociatedProducts.Select(x => x.Name)))
                     .And(Infer.Field<ElasticIndexGroupProduct>(p => p.AssociatedProducts.Select(x => x.CategoryName)))                        
                     .And(Infer.Field<ElasticIndexGroupProduct>(p => p.AssociatedProducts.Select(x => x.ManufacturerName)))
                     .And(Infer.Field<ElasticIndexGroupProduct>(p => p.AssociatedProducts.Select(x => x.ShortDescription))),
            Boost = 1.1,
            Name = "named_query",
            Query = searchQuery,
            DefaultOperator = Operator.Or,
            Analyzer = "standard",
            QuoteAnalyzer = "keyword",
            AllowLeadingWildcard = true,
            MaximumDeterminizedStates = 2,
            Escape = true,
            FuzzyPrefixLength = 2,
            FuzzyMaxExpansions = 3,
            FuzzyRewrite = MultiTermQueryRewrite.ConstantScore,
            Rewrite = MultiTermQueryRewrite.ConstantScore,
            Fuzziness = Fuzziness.Auto,
            TieBreaker = 1,
            AnalyzeWildcard = true,
            MinimumShouldMatch = 2,
            QuoteFieldSuffix = "'",
            Lenient = true,
            AutoGenerateSynonymsPhraseQuery = false
        };
        queryContainer &= multiMatch;        

        //sorting 
        var sorts = new List<ISort>();
        switch (sortBy)
        {
            case "z-a":
                sorts.Add(new FieldSort { Field = Infer.Field<ElasticIndexGroupProduct>(p => p.Name), Order = SortOrder.Descending });
                sorts.Add(new FieldSort { Field = Infer.Field<ElasticIndexGroupProduct>(p => p.AssociatedProducts.Select(x=>x.Name)), Order = SortOrder.Descending });
                break;
            default:
                sorts.Add(new FieldSort { Field = Infer.Field<ElasticIndexGroupProduct>(p => p.Name), Order = SortOrder.Ascending });
                sorts.Add(new FieldSort { Field = Infer.Field<ElasticIndexGroupProduct>(p => p.AssociatedProducts.Select(x => x.Name)), Order = SortOrder.Ascending });
                break;
        }

       var searchRequest = new SearchRequest<ElasticIndexGroupProduct>()
        {
            Profile = true,
            Query = queryContainer,
            From = (pageNumber - 1) * pageSize,
            Size = pageSize,
            Version = true,
            Sort = sorts
        };

        var searchResponse = _client.Search<ElasticIndexGroupProduct>(searchRequest);
        return GenerateSearchResult(searchQuery, searchResponse);
    }

这是错误

【问题讨论】：

标签： sorting elasticsearch .net-core nest elasticsearch-dsl

【解决方案1】：

找到了解决办法。需要在 [Keywords] 上设置 fielddata=true 以便通过反转倒排索引将 fielddata 加载到内存中。

[ElasticsearchType(RelationName = "searchproduct")]
    public class ElasticIndexGroupProduct
    {
        [Text(Fielddata = true)]
        public string Name { get; set; }
    }

【讨论】：

【解决方案2】：

如果您希望能够对 Name 执行全文搜索以及对其进行排序和聚合，那么您可能希望将其索引为具有 text 和 keyword 数据类型的 multi_field .

【讨论】：