Hi, From top of my head I can imagine two solutions:
1. Override the default behaviour of the operator via for example org.apache.flink.streaming.api.datastream.ConnectedStreams#transform 2. Can you set control stream’s watermark to Watermark#MAX_WATERMARK or maybe Watermark#MAX_WATERMARK - 1 ? Piotrek > On 24 May 2018, at 16:07, Elias Levy <fearsome.lucid...@gmail.com> wrote: > > Is there mechanism for a multiple stream operator to ignore watermarks from > one of the streams? > > The use case is a multiple stream operator that consumes a primary stream and > a secondary control stream. The control stream may only receive messages in > rare occasion, and possibly never. The default behavior of the operator is > to only emit the lowest of the last watermark received from each input > stream. That means that event time fails to advance if there are no control > messages. > > I also notice that FLIP-17, the Side Input proposal, does not address this > issue, either in the Wiki or in the Google Docs. > > Assuming there is no currently prescribed way to handle this, are folks > taking care of this by introducing a new Assigner after the multiple input > operator to generate watermarks? > >
