Drill doesn't use any such data structures in itself. The emphasis has been on being correct first with the option of introducing approximations later.
That said, you can definitely define aggregators yourself. Last I checked, however, user defined aggregators are single level ... that means that everything that gets aggregated has to go through a single function which definitely limits scalability. This was several months ago, though, so things may have improved by now. Perhaps somebody can comment on whether multi-level user-defined aggregators are possible? On Sat, Apr 30, 2016 at 8:32 AM, Edmon Begoli <[email protected]> wrote: > Is Drill using any of the probabilistic data structures [1], and if so - > which ones and how? > > Thank you, > Edmon > > 1. Probabilistic Data Structures - > https://en.m.wikipedia.org/wiki/Category:Probabilistic_data_structures >
