Tile Request slow to throw 404 error

Discussion created by mark_hiscocks on Aug 29, 2013
I have a map service on ArcGIS Server 10.1 that I am accessing using WMTS. The map covers a small region and the caching settings are to "Create tiles on demand".

I have found that when I request a tile that is within the extent of the map, it returns in less than a tenth of a second. However, if I request a tile outside of the map's extent it takes almost 2 seconds for a 404 error to be thrown. If I turn off "Create tiles on demand" on the service, the 404 is thrown almost instantly. For testing purposes I have been making the calls directly to ArcGIS and using Fiddler to trace the calls.

Is this expected behavior? I realize that I could do client-side checks to ensure the request is being made for only those tiles within the map's extent; however, that would appear to be a band-aid fix for a potential server-side issue.