Flink is a distributed system and does not preserve order across partitions.
The number prefix (e.g., 1>, 2>, ...) tells you the parallel instance of
the printing operator.
You can set the parallelism to 1 to have the stream in order.
Fabian
2017-01-05 12:16 GMT+01:00 Kostas Kloudas <k.klou...@data-artisans.com>:
> Hi Abdul,
>
> Flink provides no ordering guarantees on the elements within a window.
> The only “order” it guarantees is that the results referring to window-1
> are
> going to be emitted before those of window-2 (assuming that window-1
> precedes window-2).
>
> Thanks,
> Kostas
>
> On Jan 5, 2017, at 11:57 AM, Abdul Salam Shaikh <
> abd.salam.sha...@gmail.com> wrote:
>
> Hi,
>
> I am using a JSON file as the source for the streaming (in the ascending
> order of the field Umlaufsekunde)which has events as follows:
>
> {"event":[{"*Umlaufsekunde*":115}]}
> {"event":[{"*Umlaufsekunde*":135}]}
> {"event":[{"*Umlaufsekunde*":135}]}
> {"event":[{"*Umlaufsekunde*":145}]}
> {"event":[{"*Umlaufsekunde*":155}]}
> {"event":[{"*Umlaufsekunde*":155}]}
> {"event":[{"*Umlaufsekunde*":185}]}
> {"event":[{"*Umlaufsekunde*":195}]}
> {"event":[{"*Umlaufsekunde*":195}]}
> {"event":[{"*Umlaufsekunde*":205}]}
> {"event":[{"*Umlaufsekunde*":245}]}
>
> However, when I try to print the stream, it is unordered as given below:
> 1> (*115*,null,1483517983252,1190) -- The first value indicating
> Umlaufsekunde
> 2> (135,null,1483517984877,1190)
> 2> (155,null,1483517986861,1190)
> 4> (145,null,1483517985752,1190)
> 3> (135,null,1483517985424,1190)
> 4> (195,null,1483517990736,1190)
> 4> (255,null,1483517997424,1190)
> 2> (205,null,1483517991518,1190)
> 2> (275,null,1483517999330,1190)
> 2> (385,null,1483518865371,1190)
> 2> (395,null,1483518866840,1190)
> 1> (155,null,1483517986533,1190)
> 4> (285,null,1483518000189,1190)
> 4> (395,null,1483518866231,1190)
>
> I have also tried using the Timestamps and Watermarks but no luck as
> follows:
>
> public class TimestampExtractor implements
> AssignerWithPeriodicWatermarks<Tuple5<String,
> Long, List<Lane>, Long, Long>>{
>
> private long currentMaxTimestamp;
>
> @Override
> public Watermark getCurrentWatermark() {
> return new Watermark(currentMaxTimestamp);
> }
>
> @Override
> public long extractTimestamp(Tuple5<String, Long> element, long
> previousElementTimestamp) {
> long timestamp = element.getField(1);
> currentMaxTimestamp = timestamp;
> return currentMaxTimestamp;
> }
>
> }
>
> Could anyone suggest how do I handle this problem for the arrival of
> events in order ?
>
> Thanks!
>
>
>
>
