Hi, to answer this question, we would first need to know what you mean by „global windows“: using „windowAll()“ or „GlobalWindows“? Also, the answer might depend on the Flink version that you are using.
Best, Stefan > Am 07.05.2017 um 23:23 schrieb Adrienne Kole <adrienneko...@gmail.com>: > > Hi, > > I am doing simple aggregation with a keyed and global windows in flink. > When I compare the keyed window aggregation with 1 key and global window > (which has parallelism 1) I would expect that both of them would have similar > performance. > > However, keyed stream with 1 key performs with 2x more throughput than global > window. > My configuration is 8 node cluster, 16 core in each node, parallelism = 128. > > AFAIK, Flink doesn't manage skew by default and uses hash function to assign > keys to partitions. So if I have 1 key only, it should go to only one > partition always, which is semantically similar to global windows in flink. > > What can be the reason behind this difference in performance? > > Thanks, > Adrienne
