I'm trying to publish a large dataset (about 1GB as a shapefile) as a tiled service to a server running 10.2. It needs to be available for all zoom levels (0-19), but that would be too may tiles at the larger levels. So I'd like to pre-render levels 0-12, then cache the rest on demand. The first part, is no problem; I've published the service and successfully created the pre-rendered tiles. However, the on demand tiles are unacceptably slow, taking up to several minutes to return and/or returning empty responses. I've made sure the dataset has a spatial index and dynamic rendering is quite fast at that level.
I've previously had this dataset published on Server 10.0 and it worked fine with on demand tiles. I've also tried upgrading to Server 10.3. This fixed the issue with empty responses, but the response times are still unacceptably long. The pattern of responses is odd, too: some tiles will come back within 10 seconds, others will take up to a minute, and a few will take up to two minutes.
I know that on demand tiles require generating supertiles, but even given that, the on demand tiles are incredibly slow.