mapWithState uses HashPartitioner by default. You can use "StateSpec.partitioner" to set your custom partitioner.
On Sun, Jan 17, 2016 at 11:00 AM, Lin Zhao <l...@exabeam.com> wrote: > When the state is passed to the task that handles a mapWithState for a > particular key, if the key is distributed, it seems extremely difficult to > coordinate and synchronise the state. Is there a partition by key before a > mapWithState? If not what exactly is the execution model? > > Thanks, > > Lin > >