如何使用數據庫調用優化和加速異步方法

Question

大家好，感謝您提前幫助我。 以下問題可能聽起來很愚蠢和不正確，但我是一個初學者。

我有一種方法可以從我的數據庫中獲取一些信息，並使用 post call 和 patch call 將其發送到外部數據庫，以防信息發生變化。 我使用 EF 框架。 在那個 db 表中至少有 165k 行。

我的問題如下：有沒有辦法優化和加速所有過程？ 也許使用多線程，並行性？ 我是一個初學者，我希望你們中的一些人能幫助我理解。

方法如下：

public async Task<List<dynamic>> SyncOrdersTaskAsync(int PageSize)
{
    int PageIndex = 0;

    if (PageSize <= 0) PageSize = 100;

    const string phrase = "The fields order, task_code must make a unique set";

    var sorting = new SortingCriteria {
        Properties = new string[] { "WkOpenDate ASC" } };

    List<dynamic> listTest = new List<dynamic>();

    using (var uow = this.Factory.BeginUnitOfWork())
    {
        var repo = uow.GetRepository<IWorkOrderRepository>();

        var count = await repo.CountAllAsync();

        count = 150;

        for (PageIndex = 0; PageIndex <= count / PageSize; PageIndex++)
        {
            var paging = new PagingCriteria
            {
                PageIndex = PageIndex,
                PageSize = PageSize
            };

            var rows = await repo.GetByCriteriaAsync(
                "new {WkID, CompanyID, JobNo, JobTaskNo ,WkNumber, WkYear," +
                "WkYard,WkCustomerID,CuName,WkDivisionID,DvName,BusinessUnit," +
                "BusinessUnitManagerID,BusinessUnitManager,WkWorkTypeID,WtName," +
                "WkActivityID,WkActivityDescription,NoteDescrLavoro,WkWOManagerID," +
                "ProjectManager,IDMaster,ProjectCoordinator,WkOpenDate," +
                "WkDataChiusa,Prov,CodiceSito,CodiceOffice,CodiceLavorazione," +
                "CodiceNodo,DescrizioneNodo,WkPrevisionalStartDate,WkRealStartDate," +
                "WkPrevisionalEndDate,WkRealEndDate,NumeroOrdine," +
                "WkPrevisionalLabourAmount,TotaleCosti,SumOvertimeHours," +
                "SumTravelHours,SumNormalHours,WkProgressPercentage,Stato,CUP,CIG," +
                "TotaleManodopera,TotalePrestazioni,TotaleNoli,TotaleMateriali," +
                "SumAuxiliaryHours,TipoCommessa,TotaleOrdine, WkPreventivoData," +
                "WkConsuntivoData,TotaleFatturato,AggregateTotaleFatturato," +
                "AggregateTotalePrestazioni,Contract,CustomerOrderNumber," +
                "XmeWBECode,LastUpdateDate,PreGestWkID,CommercialNotes,Mandant," +
                "GammaProjectName,WkInventoryDate,WkCloseFlag,WkNote," +
                "TotalRegisteredLabour,TotalRegisteredPerformances," +
                "TotalRegisteredLeasings,TotalRegisteredMaterials,FlagFinalBalance," +
                "FinalBalance,OrderDate,TotalOrderDivision,SearchDescription," +
                "TotaleBefToBeApproved,TotaleBefToBeApprovedLeasings," +
                "TotaleLabourToBeApproved,AggregateLevel, AggregateTotalLabour," +
                "AggregateTotalLeasings,AggregateTotalMaterials," +
                "AggregateTotalRegisteredLabour," +
                "AggregateTotalRegisteredPerformances," +
                "AggregateTotalRegisteredLeasings," +
                "AggregateTotalRegisteredMaterials," +
                "AggregateTotalCost,AggregateSumNormalHours," +
                "AggregateSumAuxiliaryHours,AggregateSumRainHours," +
                "AggregateSumTravelHours,AggregateSumOvertimeHours," +
                "AggregateWkPrevisionalLabourAmount,AggregateFinalBalance," +
                "AggregateTotalOrder,AggregateTotalOrderDivision," +
                "AggregateTotalBefToBeApproved," +
                "AggregateTotalBefToBeApprovedLeasings," +
                "AggregateTotalLabourToBeApproved,TotalProduction," +
                "AggregateTotalProduction,JobTaskDescription}", paging, sorting);

            String url = appSettings.Value.UrlV1 + "order_tasks/";

            using (var httpClient = new HttpClient())
            {
                httpClient.DefaultRequestHeaders.Add("Authorization", "Token " +
                    await this.GetApiKey(true));
                if (rows.Count() > 0)
                {
                    foreach (var row in rows)
                    {
                        var testWork = (Model.WorkOrderCompleteInfo)Mapper
                            .MapWkOrdersCompleteInfo(row);
                        var orderIdDiv = await this.GetOrderForSyncing(httpClient,
                            testWork.JobNo);
                        var jsonTest = new JObject();
                        jsonTest["task_code"] = testWork.JobTaskNo;
                        jsonTest["description"] = testWork.JobTaskDescription;
                        jsonTest["order"] = orderIdDivitel.Id;
                        jsonTest["order_date"] = testWork.OrderDate.HasValue
                            ? testWork.OrderDate.Value.ToString("yyyy-MM-dd")
                            : string.IsNullOrEmpty(testWork.OrderDate.ToString())
                                ? "1970-01-01"
                                : testWork.OrderDate.ToString().Substring(0, 10);
                        jsonTest["progress"] = testWork.WkProgressPercentage;

                        var content = new StringContent(jsonTest.ToString(),
                            Encoding.UTF8, "application/json");
                        var result = await httpClient.PostAsync(url, content);
                        if (result.Content != null)
                        {
                            var responseContent = await result.Content
                                .ReadAsStringAsync();
                            bool alreadyExists = phrase.All(responseContent.Contains);

                            if (alreadyExists)
                            {
                                var taskCase = await GetTaskForSyncing(httpClient,
                                    testWork.JobTaskNo, orderIdDiv.Id.ToString());
                                var idCase = taskCase.Id;
                                String urlPatch = appSettings.Value.UrlV1 +
                                    "order_tasks/" + idCase + "/";
                                bool isSame = taskCase.Equals(testWork
                                    .toSolOrderTask());
                                if (!isSame)
                                {
                                    var resultPatch = await httpClient.PatchAsync(
                                        urlPatch, content);
                                    if (resultPatch != null)
                                    {
                                        var responsePatchContent = await resultPatch
                                            .Content.ReadAsStringAsync();
                                        var jsonPatchContent = JsonConvert
                                            .DeserializeObject<dynamic>(
                                            responsePatchContent);
                                        listTest.Add(jsonPatchContent);
                                    }
                                }
                                else
                                {
                                    listTest.Add(taskCase.JobTaskNo_ +
                                        " is already updated!");
                                }
                            }
                            else
                            {
                                var jsonContent = JsonConvert
                                    .DeserializeObject<dynamic>(responseContent);
                                listTest.Add(jsonContent);
                            }
                        }
                    }
                }
            }
        }

        return listTest;
    }
}

也許我需要在 for 循環中應用並行性？

再次，真的提前感謝大家，我希望我很清楚:)

Answer 1

當前可用於並行化異步工作的最方便的工具是Parallel.ForEachAsync方法。 它是在 .NET 6 中引入的。盡管您的代碼非常復雜，並且決定將這個循環放在哪里並不明顯。

理想情況下，您只想調用Parallel.ForEachAsync一次，以便它從頭到尾以單一可配置的並行度並行化您的工作。 通常你不想把這個方法放在一個外部for / foreach循環中，因為那樣的話並行度會在整個操作過程中發生波動。 但是由於您的代碼很復雜，所以我會采用簡單的方法來做到這一點。 我會替換這段代碼：

foreach (var row in rows)
{
    //...
}

...有了這個：

ParallelOptions options = new() { MaxDegreeOfParallelism = 2 };
await Parallel.ForEachAsync(rows, options, async (row, _) =>
{
    //...
});

你必須再做一次改變。 List<T>不是線程安全的，因此如果您在沒有同步的情況下從多個線程調用Add ，它將被損壞。 您可以在每個listTest.Add之前添加一個lock (listTest) ，或者將其替換為並發集合。 我的建議是稍后做：

ConcurrentQueue<dynamic> listTest = new();
//...
listTest.Enqueue(jsonContent);
//...
return listTest.ToList();

完成這些更改后，希望您的代碼仍能正常工作，並且運行速度會更快一些。 然后，您必須嘗試使用MaxDegreeOfParallelism設置，直到找到能夠產生最佳性能的設置。 不要對像 100 或 1000 這樣的大值發瘋。在大多數情況下，過度並行化是有害的，並且可能會產生比完全不並行化更差的性能。