Question

我的网络服务响应时间非常慢，这是我第一次使用Async / await选项但不确定它是否正确。如果我直接查询表，它只需要大约3秒。但现在需要更长的时间。

我想要做的是找出哪些程序被激活（可见给用户），并在第一步中加载ProgramCode，ReleaseDate和ProgramMetadata表获取ProgramName（包括：系列选项，做一些合并）其余的可以加载后。这实际上是否可行，如果可行，我需要做些什么改变才能实现这个目标？我附上了网络服务代码：

[Route("Programs/{id_activation_state}")]
    public async Task<HttpResponseMessage> GetProgramByActivationState(int id_activation_state)
    {
        List<Program> ListPrograms = new List<Program>();

        foreach (var item in await db.Program.Where(p => p.id_program_activationState == id_activation_state).OrderBy(pg => pg.ProgramCode).ToListAsync())
        {
            Program programReturned = new Program();
            programReturned.id_program = item.id_program;
            programReturned.ReleaseDate = item.ReleaseDate;
            programReturned.ProgramCode = item.ProgramCode;
            programReturned.Duration = item.Duration;
            programReturned.ImdbCode = item.ImdbCode;
            programReturned.id_program_rating = item.id_program_rating;
            programReturned.id_program_activationState = item.id_program_activationState;
            programReturned.DefaultLanguage = item.DefaultLanguage;
            programReturned.ProgramType = item.ProgramType;
            programReturned.ListingGenre = item.ListingGenre;
            programReturned.ListingGenre1 = item.ListingGenre1;
            programReturned.ListingGenre2 = item.ListingGenre2;


            if (item.ProgramMetadata.Count > 0)
            {
                ProgramMetadata PM = new ProgramMetadata();
                PM = item.ProgramMetadata.Where(pm => pm.id_language == item.DefaultLanguage).FirstOrDefault();
                PM.ProgramActivationState = null;
                if (item.ProgramType == 3)
                {
                    var query = from ps in db.ProgramSerie
                                join pss in db.ProgramSerieSeason on ps.id_program_serie equals pss.id_program_serie
                                join pse in db.ProgramSerieEpisode on pss.id_program_serie_season equals pse.id_program_season
                                where pse.id_program == item.id_program
                                select new
                                {
                                    SerieName = ps.SerieName,
                                    Season = pss.SeasonNumber,
                                    Episode = pse.EpisodeNumber
                                };

                    if (query.Count() > 0)
                        PM.ProgramName = query.First().SerieName.Trim() + ": " + PM.ProgramName.Trim() + ", S" + query.First().Season + "E" + query.First().Episode;


                }

                programReturned.ProgramMetadata.Add(PM);
            }
            ListPrograms.Add(programReturned);
        }
        return Request.CreateResponse(HttpStatusCode.OK, new { Program = ListPrograms });
    }

Answer 1

Await和Async运行代码不并行它只是不阻塞主线程。这样UI就可以绘制了。但在控制器需要其他东西。你可以尝试Parallel.For ... MSDN Parallel for

但我认为您应该重新考虑您的架构。呼叫被阻止，直到查询结束。更好的是你发送请求并离开控制器方法。在后台线程中运行查询，最后通过signalR发送答案......

使用Async / Await等慢速Web服务

1 个答案: