On Mon, Feb 9, 2015 at 1:04 PM, Adam Fuchs <[email protected]> wrote:
> 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. > Yes. However, do not attempt to insert identical keys in a single mutation. Only one will be kept, whether versioning is enabled or not. Billie > > 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. >
