Slow instantiation of iTextSharp PdfReader with large fillable form

I have a large (6 pages, 222 fields) fillable PDF that I am using as a template with iTextSharp PdfReader. When this object instantiates it takes 5 minutes or more. I have tried:

string pdfPath = Path.Combine(context.Server.MapPath("~/apps/ssgenpdf/App_Data"), "07-2011 Worksheets.pdf");
reader = new PdfReader(pdfPath);

alternatively I have tried reading the file into a memory stream and passing the memory stream to the PdfReader constructor. Additionally I have tried using:

reader = new PdfReader(new RandomAccessFileOrArray(pdfPath), null);

none of these alternatives show significant gains.

This is an ASP.Net app, and so my interim solution is to do this creation on application start and caching the reader, then I check to see if I get a valid reader from the cache and instantiate a new reader from that reader. Now I routinely see under 50 millisecond response from this approach.

My concern is that this does not seem scalable if others in my group want to use this "fillable PDF a开发者_如何学Pythons template with iTextSharp" strategy. Does anyone have any suggestions for alternate strategies to balance performance with scalability?

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Make sure the PDF you are using are same on the server as well as locally.sometime from source control they get corrupted.[I have face the issue with VSS with fillable pdf forms which i have created via nitro.] Also better to ask the question and relevant forum http://forum.pdfsharp.net