Slow first call to C# web service

Question

I am trying to access the PubMed web services as provided here:

http://www.ncbi.nlm.nih.gov/entrez/eutils/soap/v2.0/DOC/esoap_help.html

I wrote code in java to access the web service and the return times were on the order of less than 1 second. I wrote code in C# to access the same web service and the return times were on the order of 12 seconds for the initial call and then less than 1 second for all subsequent calls.

I have tried to write to the web service in C# in two ways - both as console applications. First was the standard "right click on references and do 'Add Service Reference'" which will add information to app.config and you can make the calls nice and easy. The second was to use wsdl.exe to create a dll and access the web service as "directly" as possible (no wizards). Both ways offer the same result. I will post both of the respective code snips.

1) (from Add Service Reference wizard)

http://www.ncbi.nlm.nih.gov/entrez/eutils/soap/v2.0/efetch_pubmed.wsdl (as Namespace: PubMedWebServiceEfetch_pubMed)

(in code)

Stopwatch sw = new Stopwatch();
PubMedWebServiceEfetch_pubMed.eUtilsServiceSoapClient server = new PubMedWebServiceEfetch_pubMed.eUtilsServiceSoapClient();
try
{
    PubMedWebServiceEfetch_pubMed.eFetchRequest searchRequest = new PubMedWebServiceEfetch_pubMed.eFetchRequest();
    searchRequest.id = "11850928";
    Console.WriteLine("Run server.run_eFetch(theRequest).  [Reset stopwatch]");
    sw.Restart();
    PubMedWebServiceEfetch_pubMed.eFetchResult searchResult = server.run_eFetch(searchRequest);
    Console.WriteLine(searchResult.Count() + " - elapsed milliseconds = " + sw.ElapsedMilliseconds);
    sw.Stop();
}
catch (Exception e1) { Console.WriteLine(e1); }
finally { server.Dispose(); } 

2) (from command line)

wsdl /out:myProxyClassPubMed.cs http://eutils.ncbi.nlm.nih.gov/soap/v2.0/efetch_pubmed.wsdl
csc /t:library MyProxyClassPubMed.cs

(add dll to console app)

Stopwatch sw = new Stopwatch();
eFetchPubmedService service = new eFetchPubmedService();
try
{
    eFetchRequest theRequest = new eFetchRequest();
    theRequest.id = "11850928";
    Console.WriteLine("Run service.run_eFetch(theRequest).  [Reset stopwatch]");
    sw.Restart();
    eFetchResult searchResult = service.run_eFetch(theRequest);
    Console.WriteLine(searchResult.Count() + " - elapsed milliseconds = " + sw.ElapsedMilliseconds);
    sw.Stop();
}
catch (Exception e1) { Console.WriteLine(e1); }
finally { service.Dispose(); }

After much searching I found that you are supposed to be able to use sgen to create a XML Serializer. I ran:

sgen /a:myProxyClassPubMed.dll /f

This created a dll myProxyClassPubMed.XmlSerializers.dll which I then added as a reference in the second connection type.

I have also messed with the "Generate serialization assembly" option in the build area of the app and found no improvement.

I would like to make these web service calls through an ASP.NET page so twelve second return times on the first call are unacceptable.

I considered positing this on BioStar but it is not as well attended as this forum. I may do that if no answers are found here.

Any ideas?

Answer 1

The first call opens the channel (which is relatively expensive) and the second call utilizes that already open channel (less expensive).