CODEWITHSUNDEEP
c#web-servicesasynchronous
retslig
retslig

Reputation: 928

Boosting performance on async web calls

Backgound: I must call a web service call 1500 times which takes roughly 1.3 seconds to complete. (No control over this 3rd party API.) total Time = 1500 * 1.3 = 1950 seconds / 60 seconds = 32 minutes roughly.

I came up with what I though was a good solution however it did not pan out that great. So I changed the calls to async web calls thinking this would dramatically help my results it did not.

Example Code:

Pre-Optimizations:

foreach (var elmKeyDataElementNamed in findResponse.Keys)
{

    var getRequest = new ElementMasterGetRequest
    {
        Key = new elmFullKey
        {
            CmpCode = CodaServiceSettings.CompanyCode,
            Code = elmKeyDataElementNamed.Code,
            Level = filterLevel
        }
    };

    ElementMasterGetResponse getResponse;
    _elementMasterServiceClient.Get(new MasterOptions(), getRequest, out getResponse);
    elementList.Add(new CodaElement { Element = getResponse.Element, SearchCode = filterCode });
}

With Optimizations:

var tasks = findResponse.Keys.Select(elmKeyDataElementNamed => new ElementMasterGetRequest
    {
        Key = new elmFullKey
            {
                CmpCode = CodaServiceSettings.CompanyCode,
                Code = elmKeyDataElementNamed.Code,
                Level = filterLevel
            }
    }).Select(getRequest => _elementMasterServiceClient.GetAsync(new MasterOptions(), getRequest)).ToList();

Task.WaitAll(tasks.ToArray());

elementList.AddRange(tasks.Select(p => new CodaElement
    {
        Element = p.Result.GetResponse.Element,
        SearchCode = filterCode
    }));

Smaller Sampling Example: So to easily test I did a smaller sampling of 40 records this took 60 seconds with no optimizations with the optimizations it only took 50 seconds. I would have though it would have been closer to 30 or better.

I used wireshark to watch the transactions come through and realized the async way was not sending as fast I assumed it would have.

Async requests captured Async requests captured

Normal no optimization Normal no optimization You can see that the asnyc pushes a few very fast then drops off... Also note that between requests 10 and 11 it took nearly 3 seconds.

Is the overhead for creating threads for the tasks that slow that it takes seconds? Note: The tasks I am referring to are the 4.5 TAP task library.

Why wouldn't the request come faster than that. I was told the Apache web server I was hitting could hold 200 max threads so I don't see an issue there..

Am I not thinking about this clearly? When calling web services are there little advantages from async requests? Do I have a code mistake? Any ideas would be great.

Upvotes: 2

Views: 1304

Answers (1)

retslig
retslig

Reputation: 928

After many days of searching I found this post that solved my problem: Trying to run multiple HTTP requests in parallel, but being limited by Windows (registry)

The reason that the request was not hitting the server quicker was due too the my client side code and nothing to do with the server. By default C# only allows 2 concurrent requests. see here: http://msdn.microsoft.com/en-us/library/system.net.servicepointmanager.defaultconnectionlimit.aspx

I simply added this line of code and then all request came through in milliseconds. 

System.Net.ServicePointManager.DefaultConnectionLimit = 50;

enter image description here

Upvotes: 2

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