c# - WCF client hangs on response

Question

I have a WCF client (running on Win7) pointing to a WebSphere service.

All is good from a test harness (a little test fixture outside my web app) but when my calls to the service originate from my web project one of the calls (and only that one) is extremely slow to deserialize (it takes minutes VS seconds) and not just the first time.

I can see from fiddler that the response comes back quickly but then the WCF client hangs on the response itself for more than a minute before the next line of code is hit by the debugger, almost if the client was having trouble deserializing. This happens only if in the response I have a given pdf string (the operation generates a pdf), base64 encoded chunked. If for example the service raises a fault (thus the pdf string is not there) then the response is deserialized immediately.

Again, If I send the exact same envelope through Soap-UI or from outside the web project all is good.

I am at loss - What should I be looking for and is there some config setting that might do the trick?

Any help appreciated!

EDIT:

I coded a stub against the same service contract. Using the exact same basicHttpBinding and returning the exact same pdf string there is no delay registered. I think this rules out the string and the binding as a possible cause. What's left?

Answer 1

Changing transferMode="Buffered" into transferMode="Streamed" on the binding did the trick!

So the payload was apparently being chunked in small bits the size of the buffer.

I thought the same could have been achieved by increasing the buffersize (maxBufferSize="1000000") but I had that in place already and it did not help.