I have a WPF
client requesting data via WCF
service hosted in IIS 7
. The service method makes a call to a stored procedure (SQL 2012
As I suggested in the comments, please try setting transfermode to streamed to rule out the possibility that this is an issue related to memory pressure (since stream mode should cause wcf to utilize less memory).
When I saw this issue suspected this might be the problem because it only seems to happen to you when making many service calls in rapid succession. In my experience this is often one of two problems: either the proxies aren't being properly closed from the client, or the server is running GC's due to memory pressure.
When the transfermode is buffered, WCF loads the entire dataset for the message response into memory before sending it back to the client. Streamed simply sends the data back without buffering. It tends to be much faster for large data sets, slightly slower for small data sets, and always utilizes less memory(on both the server and client).