hpcc-systems/HPCC-Platform — pull request #1759 by ghalliday (2012-03-02 20:25:36+00:00)
Title: Implement a SHUFFLE activity and keyword

- New SHUFFLE keyword (provisional)
SHUFFLE(ds, { grouping }, { sort }, options);
Equivalent to
UNGROUP(SORT(GROUP(ds, grouping, options), sort));

- Add options to
* Translate SHUFFLE operations to equivalent if engines don't support it
* Create SHUFFLE for the inputs to thor local joins if possible.
* Use SHUFFLE instead of a SORT if that is possible.
* Use shuffle to reorder join conditions if one side is already sorted

- Fix minor bug - NOSORT(RIGHT) ignored on a join
- Fix minor bugs with sort tracking in and out of groups.
- Improve display of local sort using group sort in graph.
- Improve graph meta for graph result reading.

Signed-off-by: Gavin Halliday