Subject Re: Sort error No free space found in temporary...
From what i can read on the internet TempCacheLimit, is per server process, and not per attachment. 

I believe I have found the statements that caused the problem, first one was executede about 400/second and contained a union, that was replaced by union all in the hope that would eliminate the need for temp cache. 
The second statement is a really nasty dynamically build common table expression containing upwards of 10 union.. Here we are in the process of moving this search to Elastisearch.

We just purchased FB TraceManager at our company to weed performance issues  - Thanks for a great product : )