如何在Linq中提高此查询性能？

Question

我有一个大表，想知道是否可以提高查询性能。

allDocumentsWithPersianMonth有25000000记录

    var normalDocuments = allDocumentsWithPersianMonth.Where(x => x.DocumentTypeId != 8 && x.DocumentTypeId != 9);
    var debitOpening = allDocumentsWithPersianMonth.Where(x => x.DocumentTypeId == 8);
    var creditOpening = allDocumentsWithPersianMonth.Where(x => x.DocumentTypeId == 8);
    var debitClosing = allDocumentsWithPersianMonth.Where(x => x.DocumentTypeId == 9);
    var creditClosing = allDocumentsWithPersianMonth.Where(x => x.DocumentTypeId == 9);

    return allDocumentsWithPersianMonth
        .GroupBy(x => new { x.DetailId, x.DetailCode, x.DetailDescription, x.PersianMonth })
        .Select(g => new AccountsAgingViewModel
        {
            DetailId = g.Key.DetailId,
            DetailCode = g.Key.DetailCode,
            DetailDescription = g.Key.DetailDescription,
            FarvardinDebit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 1).Sum(x => x.Debit),
            OrdibeheshtDebit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 2).Sum(x => x.Debit),
            KhordadDebit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 3).Sum(x => x.Debit),
            TirDebit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 4).Sum(x => x.Debit),
            MordadDebit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 5).Sum(x => x.Debit),
            ShahrivarDebit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 6).Sum(x => x.Debit),
            MehrDebit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 7).Sum(x => x.Debit),
            AbanDebit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 8).Sum(x => x.Debit),
            AzarDebit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 9).Sum(x => x.Debit),
            DeyDebit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 10).Sum(x => x.Debit),
            BahmanDebit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 11).Sum(x => x.Debit),
            EsfandDebit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 12).Sum(x => x.Debit),
            FarvardinCredit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 1).Sum(x => x.Credit),
            OrdibeheshtCredit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 2).Sum(x => x.Credit),
            KhordadCredit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 3).Sum(x => x.Credit),
            TirCredit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 4).Sum(x => x.Credit),
            MordadCredit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 5).Sum(x => x.Credit),
            ShahrivarCredit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 6).Sum(x => x.Credit),
            MehrCredit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 7).Sum(x => x.Credit),
            AbanCredit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 8).Sum(x => x.Credit),
            AzarCredit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 9).Sum(x => x.Credit),
            DeyCredit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 10).Sum(x => x.Credit),
            BahmanCredit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 11).Sum(x => x.Credit),
            EsfandCredit = normalDocuments.Where(x => x.DetailId == g.Key.DetailId && x.PersianMonth == 12).Sum(x => x.Credit),
            DebitSumOpening = debitOpening.Where(y => y.DetailId == g.Key.DetailId).Sum(x => x.Debit),
            DebitSumClosing = debitClosing.Where(y => y.DetailId == g.Key.DetailId).Sum(x => x.Credit),
            CreditSumOpening = creditOpening.Where(y => y.DetailId == g.Key.DetailId).Sum(x => x.Debit),
            CreditSumClosing = creditClosing.Where(y => y.DetailId == g.Key.DetailId).Sum(x => x.Credit),
        })

    .ToList();

Answer 1

您应该首先消除相同查询的执行。 例如，检查以下方法。 我们每次只迭代一次并根据月份对文档进行分组，而不是normalDocuments每次迭代normalDocuments 。 然后我们创建一个带有密钥PersianMonth的字典，并为相应的Debit总和值。

这样做我们将从24次迭代变为1次。然后我们定义一个func来从该字典中获取一个月的借方或贷方的值。 从您的模型中，存款可能是借记卡或信用卡。 因此，通过传递布尔参数isDebit您将确定是否要读取Debit或Credit的值。

这个定义可能需要一些改变 ，因为我不知道Debit和Credit的类型，我只是假设这是一个decimal 。

 .Select(g => 
 {
     var groupedDocuments = normalDocuments
                                .Where(x => x.DetailId == g.Key.DetailId)
                                .GroupBy(x => x.PersianMonth)
                                .ToDictionary(x => x.Key, 
                                              x => new DepositTypes(x.Sum(y=>y.Debit), x.Sum(y=>y.Credit));

     Func<int, bool, decimal> getValueFunc = (id, isDebit) 
         => groupedDocuments.TryGetValue(id, out var value) 
                ? (isDebit ? value.Debit ?? value.Credit) 
                : 0;

     return new AccountsAgingViewModel
     {
        DetailId = g.Key.DetailId,
        DetailCode = g.Key.DetailCode,
        DetailDescription = g.Key.DetailDescription,
        FarvardinDebit = getValueFunc(1, isDeposit: true);
        OrdibeheshtDebit = getValueFunc(2, isDeposit: true);
        // etc.
     };
}

private class DepositTypes
{
    public decimal Debit { get; }
    public decimal Credit {get; }

    public DepositTypes(decimal debit, decimal credit)
    {
        Debit = debit;
        Credit = credit;
    }
}

Answer 2

试试这段代码：

 var normalDocuments = allDocumentsWithPersianMonth.Where(x => x.DocumentTypeId != 8 && x.DocumentTypeId != 9);
        var debitOpening = allDocumentsWithPersianMonth.Where(x => x.DocumentTypeId == 8);
        var creditOpening = allDocumentsWithPersianMonth.Where(x => x.DocumentTypeId == 8);
        var debitClosing = allDocumentsWithPersianMonth.Where(x => x.DocumentTypeId == 9);
        var creditClosing = allDocumentsWithPersianMonth.Where(x => x.DocumentTypeId == 9);


        return allDocumentsWithPersianMonth
            .GroupBy(x => new { x.DetailId, x.DetailCode, x.DetailDescription, x.PersianMonth })
                   .Select(g =>
                   {
                       var filteredDocuments = normalDocuments.Where(x => x.DetailId == g.Key.DetailId);
                       var m1 = filteredDocuments.Where(x => x.PersianMonth == 1);
                       var m2 = filteredDocuments.Where(x => x.PersianMonth == 3);
                       var m3 = filteredDocuments.Where(x => x.PersianMonth == 4);
                       var m4 = filteredDocuments.Where(x => x.PersianMonth == 5);
                       var m5 = filteredDocuments.Where(x => x.PersianMonth == 6);
                       var m6 = filteredDocuments.Where(x => x.PersianMonth == 7);
                       var m7 = filteredDocuments.Where(x => x.PersianMonth == 8);
                       var m8 = filteredDocuments.Where(x => x.PersianMonth == 9);
                       var m9 = filteredDocuments.Where(x => x.PersianMonth == 2);
                       var m10 = filteredDocuments.Where(x => x.PersianMonth == 10);
                       var m11 = filteredDocuments.Where(x => x.PersianMonth == 11);
                       var m12 = filteredDocuments.Where(x => x.PersianMonth == 12);

                       return new AccountsAgingViewModel
                       {
                           DetailId = g.Key.DetailId,
                           DetailCode = g.Key.DetailCode,
                           DetailDescription = g.Key.DetailDescription,
                           FarvardinDebit = m1.Sum(x => x.Debit),
                           OrdibeheshtDebit = m2.Sum(x => x.Debit),
                           KhordadDebit = m3.Sum(x => x.Debit),
                           TirDebit = m4.Sum(x => x.Debit),
                           MordadDebit = m5.Sum(x => x.Debit),
                           ShahrivarDebit = m6.Sum(x => x.Debit),
                           MehrDebit = m7.Sum(x => x.Debit),
                           AbanDebit = m8.Sum(x => x.Debit),
                           AzarDebit = m9.Sum(x => x.Debit),
                           DeyDebit =m10.Sum(x => x.Debit),
                           BahmanDebit = m11.Sum(x => x.Debit),
                           EsfandDebit = m12.Sum(x => x.Debit),
                           FarvardinCredit =m1.Sum(x => x.Credit),
                           OrdibeheshtCredit = m2.Sum(x => x.Credit),
                           KhordadCredit = m3.Sum(x => x.Credit),
                           TirCredit = m4.Sum(x => x.Credit),
                           MordadCredit = m5.Sum(x => x.Credit),
                           ShahrivarCredit = m6.Sum(x => x.Credit),
                           MehrCredit = m7.Sum(x => x.Credit),
                           AbanCredit = m8.Sum(x => x.Credit),
                           AzarCredit = m9.Sum(x => x.Credit),
                           DeyCredit = m10.Sum(x => x.Credit),
                           BahmanCredit = m11.Sum(x => x.Credit),
                           EsfandCredit = m12.Sum(x => x.Credit),
                           DebitSumOpening = debitOpening.Where(y => y.DetailId == g.Key.DetailId).Sum(x => x.Debit),
                           DebitSumClosing = debitClosing.Where(y => y.DetailId == g.Key.DetailId).Sum(x => x.Credit),
                           CreditSumOpening = creditOpening.Where(y => y.DetailId == g.Key.DetailId).Sum(x => x.Debit),
                           CreditSumClosing = creditClosing.Where(y => y.DetailId == g.Key.DetailId).Sum(x => x.Credit),
                       };
                   })
        .ToList();

更新

Christos代码比这更好。 我已经测试了400 recrod Christos代码仅需要18839 ms，我的代码需要102975ms。

这是最好的解决方案：

var normalDocuments = allDocumentsWithPersianMonth
                .GroupBy(x => new { x.DetailId, x.DetailCode, x.DetailDescription, x.PersianMonth })
                             .Select(g =>
                 {
                     var groupedDocuments = normalDocuments
                                                .Where(x => x.DetailId == g.Key.DetailId)
                                                .GroupBy(x => x.PersianMonth)
                                                .ToDictionary(x => x.Key,
                                                              x => new DepositTypes(x.Sum(y => y.Debit), x.Sum(y => y.Credit)));

                     Func<int, bool, decimal> getValueFunc = (id, isDebit)
                         => groupedDocuments.TryGetValue(id, out var value) ? (isDebit ? value.Debit : value.Credit) : 0;

                     return new AccountsAgingViewModel
                     {
                         DetailId = g.Key.DetailId,
                         DetailCode = g.Key.DetailCode,
                         DetailDescription = g.Key.DetailDescription,
                         FarvardinDebit = getValueFunc(1, true),
                         OrdibeheshtDebit = getValueFunc(2, true),
                         KhordadDebit = getValueFunc(3, true),
                         TirDebit = getValueFunc(4, true),
                         MordadDebit = getValueFunc(5, true),
                         ShahrivarDebit = getValueFunc(6, true),
                         MehrDebit = getValueFunc(7, true),
                         AbanDebit = getValueFunc(8, true),
                         AzarDebit = getValueFunc(9, true),
                         DeyDebit = getValueFunc(10, true),
                         BahmanDebit = getValueFunc(11, true),
                         EsfandDebit = getValueFunc(12, true),
                         FarvardinCredit = getValueFunc(1, false),
                         OrdibeheshtCredit = getValueFunc(2, false),
                         KhordadCredit = getValueFunc(3, false),
                         TirCredit = getValueFunc(4, false),
                         MordadCredit = getValueFunc(5, false),
                         ShahrivarCredit = getValueFunc(6, false),
                         MehrCredit = getValueFunc(7, false),
                         AbanCredit = getValueFunc(8, false),
                         AzarCredit = getValueFunc(9, false),
                         DeyCredit = getValueFunc(10, false),
                         BahmanCredit = getValueFunc(11, false),
                         EsfandCredit = getValueFunc(12, false),
                         DebitSumOpening = debitOpening.Where(y => y.DetailId == g.Key.DetailId).Sum(x => x.Debit),
                         DebitSumClosing = debitClosing.Where(y => y.DetailId == g.Key.DetailId).Sum(x => x.Credit),
                         CreditSumOpening = creditOpening.Where(y => y.DetailId == g.Key.DetailId).Sum(x => x.Debit),
                         CreditSumClosing = creditClosing.Where(y => y.DetailId == g.Key.DetailId).Sum(x => x.Credit),
                     }; 

Answer 3

一些选项要检查：

1. 查看生成的SQL查询，可能只需要添加一些索引（在执行计划的帮助下）。
2. 将所有数据加载到更具体的结构（例如，Dictionary）中，然后选择。 看起来你对DB有很多疑问。