Question

使用Task.blob将大约200 300k blob写入blob存储时，WhenAll（List）的写入挂起/花费的时间明显长于按顺序执行的时间。

我正在功能应用中运行该过程。

不起作用

private async Task WriteToBlobAsync(List<DataSeries> allData)
        {
            int blobCount = 0;
            List<Task> blobWriteTasks = new List<Task>();
            foreach(DataSeries series in allData)
            {
                blobCount++;
                string seriesInJson = JsonConvert.SerializeObject(series);
                blobWriteTasks.Add(_destinationBlobStore.WriteBlobAsync(seriesInJson, series.SaveName));
                //await _destinationBlobStore.WriteBlobAsync(seriesInJson, series.SaveName);
                if (blobCount % 100 == 0)
                {
                    _flightSummaryDoc.AddLog($"{blobCount} Blobs Complete");
                    _log.Info($"{blobCount} Blobs Complete");
                }
            }
            await Task.WhenAll(blobWriteTasks.ToArray());
        }

工作明显更快（但不应该如此）

private async Task WriteToBlobAsync(List<DataSeries> allData)
        {
            int blobCount = 0;
            List<Task> blobWriteTasks = new List<Task>();
            foreach(DataSeries series in allData)
            {
                blobCount++;
                string seriesInJson = JsonConvert.SerializeObject(series);
                //blobWriteTasks.Add(_destinationBlobStore.WriteBlobAsync(seriesInJson,series.SaveName));
                await _destinationBlobStore.WriteBlobAsync(seriesInJson, series.SaveName);
                if(blobCount % 100 == 0)
                {
                    _flightSummaryDoc.AddLog($"{blobCount} Blobs Complete");
                    _log.Info($"{blobCount} Blobs Complete");
                }
            }
            //await Task.WhenAll(blobWriteTasks.ToArray());
        }

Answer 1

由于无法处理200个并发请求，它正在缓慢运行并失败。

考虑使用SemaphorSlim来使用其内置的限制机制，并将并发请求限制为一个更合理的数目。

查看此信息：How to limit the amount of concurrent async I/O operations?

Task.WhenAll对Blob的所有写入均无法关闭或完成

1 个答案: