Hi Dave, As long as your combiner is associative and commutative both of the values should be represented in the combined result. The non-determinism is really around ordering, which generally doesn't matter for a combiner.
Adam On Mon, Feb 9, 2015 at 3:49 PM, Dave Hardcastle <[email protected]> wrote: > Hi, > > Could someone clarify whether the following statement from the manual - "If > two inserts are made into Accumulo with the same rowID, column, and > timestamp, then the behavior is non-deterministic" - applies even if the > versioning iterator is off? Is the non-determinism the fact that the order > is undetermined if two identical inserts are made and all versions are kept? > > I have an application where the key corresponds to an object and a time > range, and the value is properties of the object over that time range. The > time range is stored in the column qualifier, but I also put the end of the > time range as the timestamp of the key. I frequently get data late, and so > create a key and insert that, but that key may already exist in the table. > When multiple identical versions get put in, the values are aggregated using > a combiner. This seems to be working fine. But maybe I shouldn't be assuming > that Accumulo won't silently drop one of the two keys? > > Thanks, > > Dave.
