There's no built-in iterator to do this. It's difficult to reliably aggregate/combine data across rows. This might be better suited as a MapReduce job rather than an iterator. Even if you do something clever to aggregate within a tablet (like transform all matching keys to a fixed R/CF/CQ and then using a combiner to group them within that virtual row) and deal with the potential problems with that (reliably transforming rowIds is especially tricky), you're still going to need to aggregate across tablets with some sort of client code... either with MapReduce or a single-node client.
-- Christopher L Tubbs II http://gravatar.com/ctubbsii On Mon, Oct 14, 2013 at 12:06 PM, Korb, Michael [USA] <[email protected]> wrote: > Given a specific CF and CQ, is there an iterator I can use to get all unique > values across all rows? > > Example: > > row0 myCF:myCQ a > row1 myCF:myCQ a > row2 myCF:myCQ a > row3 myCF:myCQ b > row4 myCF:myCQ c > row5 myCF:myCQ c > > I am interested in unique values associated with myCF:myCQ (irrelevant > columns omitted from example). > > Result: a, b, c > > Thanks, > Mike
