Hi Gyorgy, To my knowledge, ordering of elements is not guaranteed. To order your elements in each window by time, you would need to sort the iterables produced by the groupByKey. You might use SortValues[1] to do that.
[1] https://beam.apache.org/documentation/sdks/java-extensions/#example-usage-of-sortvalues Thanks, Evan On Tue, May 17, 2022 at 04:35 Balogh, György <bog...@ultinous.com> wrote: > Hi, > > I have video analytic data: > - time > - object type (car, person, etc) > - object bounding box (x,y,width,height) > - track id > > I'd like to do transformations where I need to process detections > belonging to the same track in time order. > > My input data is ordered by time. I do some filtering first (eg.: filter > cars) than apply sliding windows (eg.: 10 sec window size, with 5 sec step) > and group by track id. > > Can we assume anything about the order of events in the windows? Is the > order preserved? I need to process them in time order, if the order is not > preserved what would be the best approach? I can of course collect and sort > the data but it has significant performance and memory impact. (I need to > process events on the billion scale). > > Thank you, > Gyorgy > > > -- > > György Balogh > CEO > E gyorgy.bal...@ultinous.com <zsolt.sala...@ultinous.com> > M +36 30 270 8342 <+36%2030%20270%208342> > A HU, 1117 Budapest, Budafoki út 209 > <https://www.google.com/maps/search/HU,+1117+Budapest,+Budafoki+%C3%BAt+209?entry=gmail&source=g> > . > W www.ultinous.com >
