How to do asynchronous programming when you will create a lot of tasks

Question

I have the following code options:

foreach (var e in result.ExcludedEntity)
       await ProcessExcl.processEntity(e, e.ExclusionIdentification.UeiDuns);

await Task.WhenAll(result.ExcludedEntity.Select(async e =>
    await ProcessExcl.processEntity(e, e.ExclusionIdentification.UeiDuns)));

I realize the first one will run synchronously and the second will be asynchronous.

Is there a way to limit the second to by say running in batches of 20 (I don't even know if that is ideal)?

But I can tell you that running them all at once (sometimes 7000 results) runs slower than running it synchronously.

"I realize the first one will run sync and the 2nd will be async." No, they are both asynchronous. The first runs *sequentially* and the second runs *concurrently*. Whether operations are synchronous or asynchronous is independent of whether they're sequential or concurrent. — Servy, Jul 01 '21 at 14:58
You can find some good solutions here: [How to limit the amount of concurrent async I/O operations?](https://stackoverflow.com/questions/10806951/how-to-limit-the-amount-of-concurrent-async-i-o-operations) You could also wait for the [`Parallel.ForEachAsync`](https://docs.microsoft.com/en-us/dotnet/api/system.threading.tasks.parallel.foreachasync?view=net-6.0) API, that is going to be introduced with the upcoming .NET 6. — Theodor Zoulias, Jul 01 '21 at 15:39

0 Answers0