Task.Run在for循环中

Question

我有一个for循环里面

第一: 我想计算运行所需的SQL

第二步: 异步运行SQL,无需单独等待它们循环完成

我的代码看起来像:

for (
        int i = 0;
        i < gm.ListGroupMembershipUploadDetailsInput.GroupMembershipUploadInputList.Count;
        i++)
{
     // Compute
     SQL.Upload.UploadDetails.insertGroupMembershipRecords(
         gm.ListGroupMembershipUploadDetailsInput.GroupMembershipUploadInputList[i],max_seq_key++,max_unit_key++,
         out strSPQuery,
         out listParam);

     //Run the out SPQuery async
     Task.Run(() => rep.ExecuteStoredProcedureInputTypeAsync(strSPQuery, listParam));
}

insertGroupMembershipRecords单独的DAL类中的方法如下所示:

public static GroupMembershipUploadInput insertGroupMembershipRecords(GroupMembershipUploadInput gm, List<ChapterUploadFileDetailsHelper> ch, long max_seq_key, long max_unit_key, out string strSPQuery, out List<object> parameters)
{
    GroupMembershipUploadInput gmHelper = new GroupMembershipUploadInput();
    gmHelper = gm;
    int com_unit_key = -1;
    foreach(var item in com_unit_key_lst){
        if (item.nk_ecode == gm.nk_ecode)
            com_unit_key = item.unit_key;
    }

    int intNumberOfInputParameters = 42;
    List<string> listOutputParameters = new List<string> { "o_outputMessage" };
    strSPQuery = SPHelper.createSPQuery("dw_stuart_macs.strx_inst_cnst_grp_mbrshp", intNumberOfInputParameters, listOutputParameters);
    var ParamObjects = new List<object>();

    ParamObjects.Add(SPHelper.createTdParameter("i_seq_key", max_seq_key, "IN", TdType.BigInt, 10));
    ParamObjects.Add(SPHelper.createTdParameter("i_chpt_cd", "S" + gm.appl_src_cd.Substring(1), "IN", TdType.VarChar, 4));
    ParamObjects.Add(SPHelper.createTdParameter("i_nk_ecode", gm.nk_ecode, "IN", TdType.Char, 5)); 

    // rest of the method
   }

但是在list Count我试过的2k的情况下,

它没有在DB中插入2k记录但只有1.

为什么这不插入输入列表的所有记录？

我错过了什么？

Answer 1

Task.Run 在 for 循环中

尽管这不是问题，但标题本身就是我要解决的问题。对于 CPU 密集型操作，您可以使用Parallel.Foror Parallel.ForEach，但由于我们是 IO 密集型（即数据库调用），我们应该重新考虑这种方法。

这里显而易见的答案是创建一个代表异步操作的任务列表，然后使用Task.WhenAll如下所示的 API 等待它们：

public async Task InvokeAllTheSqlAsync()
{
    var list = gm.ListGroupMembershipUploadDetailsInput.GroupMembershipUploadInputList;

    var tasks = Enumerable.Range(0, list.Count).Select(i =>
    {
        var value = list[i];
        string strSPQuery;
        List<SqlParameter> listParam;
        SQL.Upload.UploadDetails.insertGroupMembershipRecords(
            value, 
            max_seq_key++,
            max_unit_key++,
            out strSPQuery,
            out listParam
        );

        return rep.ExecuteStoredProcedureInputTypeAsync(strSPQuery, listParam);
    });

    await Task.WhenAll(tasks);
}