What does the number in front of ">" mean when I print a DataStream

[chrisr123]

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&lt;String,Double>> simpleStream = env
                                .socketTextStream(parms.get("host"), parms.getInt("port"))
                                .map(new SensorParser());

                DataStream<Tuple2&lt;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/

[Hequn Cheng]

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 <[hidden email]> 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&lt;String,Double>> simpleStream = env
                                .socketTextStream(parms.get("host"), parms.getInt("port"))
                                .map(new SensorParser());

                DataStream<Tuple2&lt;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/