Hi! The order in which the elements arrive in an iteration HEAD is the order in which the last operator in the loop (the TAIL) produces them. If that is a deterministic ordering (because of a sorted reduce, for example), then you should be able to rely on the order.
Otherwise, the order of elements can always change every time elements are re-distributed across tasks (for example during a key-based shuffle, a broadcast, or a change of parallelism). Greetings, Stephan On Mon, May 2, 2016 at 2:50 PM, Aljoscha Krettek <aljos...@apache.org> wrote: > Hi, > as I understand it the order of elements will not be preserved across > iteration supersets. But maybe some-one else knows more. > > Cheers, > Aljoscha > > On Thu, 28 Apr 2016 at 00:23 David Kim <david....@braintreepayments.com> > wrote: > >> Hello all, >> >> I read the documentation at [1] on iterations and had a question on >> whether an assumption is safe to make. >> >> As partial solutions are continuously looping through the step function, >> when new elements are added as iteration inputs will the insertion order of >> all of the elements be preserved? >> >> Example: >> >> Current partial solutions going through step function are: A, B, C. >> >> At a later time we add (in order) elements D, E. >> >> Will the iteration result always be A,B,C,D,E? >> >> References: >> >> [1] >> *https://ci.apache.org/projects/flink/flink-docs-master/apis/batch/iterations.html >> <https://ci.apache.org/projects/flink/flink-docs-master/apis/batch/iterations.html>* >> >
