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Posted to user@flink.apache.org by chrisr123 <ch...@gmail.com> on 2018/06/14 01:09:28 UTC
What does the number in front of ">" mean when I print a DataStream
What does the number in front of the ">" character mean when call print()
on a dataset?
For example I may have this in my source where I am reading a socket stream
of sensor data:
DataStream<Tuple2<String,Double>> simpleStream = env
.socketTextStream(parms.get("host"), parms.getInt("port"))
.map(new SensorParser());
DataStream<Tuple2<String,Double>> temps = simpleStream
.keyBy(0)
.window(TumblingProcessingTimeWindows.of(Time.seconds(10)))
.process(new MyProcessWindowFunction(appStartTime));
temps.print();
When I look at the output, I see something like:
1> (sensor5,98.64)
3> (sensor8,81.31)
2> (sensor3,69.55)
4> (sensor0,82.86)
What do numbers 1,3,2,4 mean, i.e. 1>, 3>, 2>, 4> on the lines above?
Thanks
--
Sent from: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/
Re: What does the number in front of ">" mean when I print a DataStream
Posted by Hequn Cheng <ch...@gmail.com>.
Hi, chris
It means there are four threads and each thread outputs a record. You can
use env.setParallelism() to change the default value(i.e., 4) to other
values.
Best, Hequn
On Thu, Jun 14, 2018 at 9:09 AM, chrisr123 <ch...@gmail.com> wrote:
>
> What does the number in front of the ">" character mean when call print()
> on a dataset?
>
> For example I may have this in my source where I am reading a socket stream
> of sensor data:
>
> DataStream<Tuple2<String,Double>> simpleStream = env
> .socketTextStream(parms.get("host"),
> parms.getInt("port"))
> .map(new SensorParser());
>
> DataStream<Tuple2<String,Double>> temps = simpleStream
> .keyBy(0)
> .window(TumblingProcessingTimeWindows.
> of(Time.seconds(10)))
> .process(new MyProcessWindowFunction(
> appStartTime));
> temps.print();
>
> When I look at the output, I see something like:
>
> 1> (sensor5,98.64)
> 3> (sensor8,81.31)
> 2> (sensor3,69.55)
> 4> (sensor0,82.86)
>
> What do numbers 1,3,2,4 mean, i.e. 1>, 3>, 2>, 4> on the lines above?
> Thanks
>
>
>
>
>
> --
> Sent from: http://apache-flink-user-mailing-list-archive.2336050.
> n4.nabble.com/
>