My understanding is : Stateful transformations are thread safe. In case of global window + stateful transformation, Beam makes sure that all values for that key must be processed on the same machine, in fact on the same thread. Only if you have a session/time window, you need to add groupbykey. Is it correct ?
Thanks, Hemali Sutaria On Wed, Mar 31, 2021 at 10:23 AM Kenneth Knowles <[email protected]> wrote: > > On Wed, Mar 31, 2021 at 10:20 AM Kenneth Knowles <[email protected]> wrote: > >> >> On Wed, Mar 31, 2021 at 10:19 AM Hemali Sutaria < >> [email protected]> wrote: >> >>> I have a global window with per-key-and-window stateful processing >>> dataflow job. Do I need groupbykey in my transform ? Thank you >>> >> > No you do not need a GroupByKey. When you use a stateful DoFn the Beam > runner will partition the data automatically by key and window. > > Kenn > > >> >>> >>> https://cloud.google.com/blog/products/gcp/writing-dataflow-pipelines-with-scalability-in-mind >>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__cloud.google.com_blog_products_gcp_writing-2Ddataflow-2Dpipelines-2Dwith-2Dscalability-2Din-2Dmind&d=DwMFaQ&c=V9IgWpI5PvzTw83UyHGVSoW3Uc1MFWe5J8PTfkrzVSo&r=gizAAGdFA7m5QsnxkMFRenvNE9IDJSHidbXk-LafTj8&m=w8YUTt_WFJLbjNZD-kVKZ5SvaTkaDMWomSaVYqm_1Bk&s=vKBpzxOdHAwbfZJK4hXknCqtzRPuAH0g-v5s3RrZUDE&e=> >>> >>> https://beam.apache.org/documentation/programming-guide/#transforms >>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__beam.apache.org_documentation_programming-2Dguide_-23transforms&d=DwMFaQ&c=V9IgWpI5PvzTw83UyHGVSoW3Uc1MFWe5J8PTfkrzVSo&r=gizAAGdFA7m5QsnxkMFRenvNE9IDJSHidbXk-LafTj8&m=w8YUTt_WFJLbjNZD-kVKZ5SvaTkaDMWomSaVYqm_1Bk&s=5RU3xh0brlUPoAlIgo7VmJxM1QtXTrvsyH6_V_e6Sio&e=> >>> >>> >>> https://beam.apache.org/blog/timely-processing/ >>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__beam.apache.org_blog_timely-2Dprocessing_&d=DwMFaQ&c=V9IgWpI5PvzTw83UyHGVSoW3Uc1MFWe5J8PTfkrzVSo&r=gizAAGdFA7m5QsnxkMFRenvNE9IDJSHidbXk-LafTj8&m=w8YUTt_WFJLbjNZD-kVKZ5SvaTkaDMWomSaVYqm_1Bk&s=U_6l4v1fTsQ1tdjeUsLsksFDnqSMqV-p3OJNr9RgWkU&e=> >>> >>> >>> Thanks, >>> Hemali Sutaria >>> >>>
