cloudera/impala — pull request #20 by superdupershant (2013-03-07 20:29:10+00:00)
Title: Fix multi-node planning of approximate distinct aggregation.

The first phase of a distributed approximate distinct aggregation is an
intermediate node and should not finalize the aggregate tuple. This was
causing incorrect results for the distinctpc() and distinctpcsa()
operators, when creating a multi-node plan. As with other aggregates
this fix does not address what happens when there is also a distinct
aggregation.