ghalliday/HPCC-Platform — comment on commit 8929e47d77ba3014e93de8c4bacd443361fa50a3
File: ecl/hqlcpp/hqliproj.cpp line 196
By ghalliday:

If shuffle wasn't implemented by converting to a grouped sort, then it would be possible to implement a native shuffle activity which worked on grouped data, and shuffled within a group. The code generator can't guaranteed that I can restore the original groups so I can't implement it while the implementations are non native.