Thanks for the info Jing, just to clarify one point, so when we set the environment time characteristics to
Processing time: We can only use processing time windows & timer. Event time: We are able to use both processing time & event time windows & timers. Processing time is always wall/clock time depending on the host running task manager so independent from the event time? Also Kafka seems to be supporting timestamp/watermark, however is there any source not supporting timestamp/watermark & possible solutions to that like a custom watermark generator? Thanks, On Mon, Jun 28, 2021 at 8:25 AM JING ZHANG <beyond1...@gmail.com> wrote: > > Hi lenduha, > > > When set the time characteristics to ProcessingTime via > > setStreamTimeCharacteristic(...) call, I cannot see watermarks in the Flink > > UI. > > The watermark would be swallowed in the case. > > > can I use Event Time Timers even if I set the > time characteristics to ProcessingTime (via > ctx.timerService().registerEventTimeTimer(...))? > > I'm afraid not. The event time Timers could not work after setting > ProcessingTime by setStreamTimeCharacteristic, > because the watermark should be swallowed in the case, so the event time > timers would not be triggered. > > > when I set the time characteristics to Event Time can I use both > processing time timers & event time timers without any problem? > > Event time timers could work, of course. Besides, explicitly using > processing-time windows and timers works in event-time mode. > Please note that In Flink1.12, the default stream time characteristic has > been changed to EventTime [1]. > > [1] > https://ci.apache.org/projects/flink/flink-docs-release-1.13/release-notes/flink-1.12/#flip-134-batch-execution-for-the-datastream-api > > Best regards, > JING ZHANG > > Deniz Koçak <lend...@gmail.com> 于2021年6月28日周一 下午2:43写道： >> >> Hi, >> >> In environment configuration when set the time characteristics to >> ProcessingTime via setStreamTimeCharacteristic(...) call, I cannot see >> watermarks in the Flink UI. I think this is expected, because >> watermarks disabled in the source (using Kafka as source)? >> >> Another point here is, can I use Event Time Timers even if I set the >> time characteristics to ProcessingTime (via >> ctx.timerService().registerEventTimeTimer(...))? As far as I >> understood from the documentation, Event Time Timers needs watermarks >> which sets the operator time, so I wonder if I can use event time >> timers in case of ProcessingTime selected in the environment? Also >> when I set the time characteristics to Event Time can I use both >> processing time timers & event time timers without any problem? >> >> Thanks,
