elasticsearch/elasticsearch — pull request #6042 by kimchy (2014-05-05 09:05:10+00:00)
Title: Remove search operation threading option

Search operation threading is an option that is not really used, and current non default implementations are flawed. Handling it also creates quite the complexity in the search handling codebase...
This is a breaking change, but one that is actually a good one, since I haven't seen/heard anybody use it, and if its used, its problematic...