Hi,
it could be what Gyula mentioned. Let me first go a bit into how the
TimestampExtractor works internally.
First, the timestamp extractor internally keeps the value of the last emitted
watermark. Then, the semantics of the TimestampExtractor are as follows :
- the result of extractTimestamp is taken and it replaces the internal
timestamp of the element
- if the result of extractWatermark is larger than the last watermark the new
value is emitted as a watermark and the value is stored
- getCurrentWatermark is called on the specified auto-watermark interval, if
the returned value is larger than the last watermark it is emitted and stored
as last watermark
What this means in your case is that the watermark can only advance if a new
element arrives, because only then is the watermark updated.
The reason why you see results if you use fromElements is that the
window-operator also emits all the windows that it currently has buffered if
the program closes. This happens in the case of fromElements because only a
finite number of elements is emitted, after which the source closes, thereby
finishing the whole program.
Cheers,
Aljoscha
> On 16 Nov 2015, at 10:42, Gyula Fóra <gyula.f...@gmail.com> wrote:
>
> Could this part of the extractor be the problem Aljoscha?
>
> @Override
> public long getCurrentWatermark() {
> return Long.MIN_VALUE;
> }
>
> Gyula
>
> Konstantin Knauf <konstantin.kn...@tngtech.com> ezt írta (időpont: 2015. nov.
> 16., H, 10:39):
> Hi Aljoscha,
>
> thanks for your answer. Yes I am using the same TimestampExtractor-Class.
>
> The timestamps look good to me. Here an example.
>
> {"time": 1447666537260, ...} And parsed: 2015-11-16T10:35:37.260+01:00
>
> The order now is
>
> stream
> .map(dummyMapper)
> .assignTimestamps(...)
> .timeWindow(...)
>
> Is there a way to print out the assigned timestamps after
> stream.assignTimestamps(...)?
>
> Cheers,
>
> Konstantin
>
>
> On 16.11.2015 10:31, Aljoscha Krettek wrote:
> > Hi,
> > are you also using the timestamp extractor when you are using
> > env.fromCollection().
> >
> > Could you maybe insert a dummy mapper after the Kafka source that just
> > prints the element and forwards it? To see if the elements come with a good
> > timestamp from Kafka.
> >
> > Cheers,
> > Aljoscha
> >> On 15 Nov 2015, at 22:55, Konstantin Knauf <konstantin.kn...@tngtech.com>
> >> wrote:
> >>
> >> Hi everyone,
> >>
> >> I have the following issue with Flink (0.10) and Kafka.
> >>
> >> I am using a very simple TimestampExtractor like [1], which just
> >> extracts a millis timestamp from a POJO. In my streaming job, I read in
> >> these POJOs from Kafka using the FlinkKafkaConsumer082 like this:
> >>
> >> stream = env.addSource(new FlinkKafkaConsumer082<
> >> (parameterTool.getRequired("topic"),
> >> new AvroPojoDeserializationSchema(),
> >> parameterTool.getProperties()))
> >>
> >> I have timestampEnabled() and the TimeCharacteristics are EventTime,
> >> AutoWatermarkIntervall is 500.
> >>
> >> The problem is, when I do something like:
> >>
> >> stream.assignTimestamps(new PojoTimestampExtractor(6000))
> >> .timeWindowAll(Time.of(1, TimeUnit.SECONDS)
> >> .sum(..)
> >> .print()
> >>
> >> env.execute();
> >>
> >> the windows never get triggered.
> >>
> >> If I use ProcessingTime it works.
> >> If I use env.fromCollection(...) instead of the KafkaSource it works
> >> with EventTime, too.
> >>
> >> Any ideas what I could be doing wrong are highly appreciated.
> >>
> >> Cheers,
> >>
> >> Konstantin
> >>
> >> [1]:
> >>
> >> public class PojoTimestampExtractor implements TimestampExtractor<Pojo> {
> >>
> >> final private long maxDelay;
> >>
> >> public PojoTimestampExtractor(long maxDelay) {
> >> this.maxDelay = maxDelay;
> >> }
> >>
> >> @Override
> >> public long extractTimestamp(Pojo fightEvent, long l) {
> >> return pojo.getTime();
> >> }
> >>
> >> @Override
> >> public long extractWatermark(Pojo pojo, long l) {
> >> return pojo.getTime() - maxDelay;
> >> }
> >>
> >> @Override
> >> public long getCurrentWatermark() {
> >> return Long.MIN_VALUE;
> >> }
> >
> >
>
> --
> Konstantin Knauf * konstantin.kn...@tngtech.com * +49-174-3413182
> TNG Technology Consulting GmbH, Betastr. 13a, 85774 Unterföhring
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