Webservice response time After Idle Timeout

I have a webservice which returns the content of a pdf.

I've noticed that when开发者_高级运维 I've left the website for a while and I call the method of the service it takes a long time to respond. Any subsequent calls take less than a second which is great.

Can someone tell me why this is? Has the service gone to sleep and needs to reinitialise?

What would be a good way around this? Is there something I could do each time that page gets visited to tell the service a request could come through very soon?

I'm assuming you're hosting the service in IIS.

Like any other web-based application, the AppDomain in which the service runs can be recycled for several reasons. One possible reason is an idle timeout.

If you don't want it to time out due to idleness, you can change the IIS settings appropriately.