You are viewing a plain text version of this content. The canonical link for it is here.

Posted to dev@flink.apache.org by Dominik Wosiński <wo...@gmail.com> on 2020/03/25 09:03:44 UTC

Re: Flink CEP greedy match of single pattern

Hey, thanks for the answer.

But if I add the *AfterMatchSkipStrategy* it simply seems to emit event by
event so in the case described above it does emit: [400], [500]
Shouldn't the *greedy* quantifier guarantee that this will be matched as
many times as possible thus creating [400, 500] ??

Thanks again.
Best Regards,
Dom.

Re: Flink CEP greedy match of single pattern

Posted by Dawid Wysakowicz <dw...@apache.org>.

Hi Dominik,

I think you are hitting a bug. The greedy quantifier does not work well
if applied for the last element of a pattern. There is a jira issue to
improve support for greedy qualifier[1].

You could work it around with adding an additional state at the end. E.g. :

Pattern.begin[AccelVector](EventPatternName,
AfterMatchSkipStrategy.skipPastLastEvent())
  .where(_.data() > Threshold)
  .oneOrMore
  .greedy
  .consecutive()
  .next("b")
  .where(BooleanConditions.true())
  .within(Time.minutes(1))

Best,

Dawid

[1] https://issues.apache.org/jira/browse/FLINK-10587



On 25/03/2020 10:07, Dominik Wosiński wrote:
> P.S.
> So now my pattern looks like this:
>
> Pattern.begin[AccelVector](EventPatternName,
> AfterMatchSkipStrategy.skipPastLastEvent())
>   .where(_.data() > Threshold)
>   .oneOrMore
>   .greedy
>   .consecutive()
>   .within(Time.minutes(1))
>
>
> śr., 25 mar 2020 o 10:03 Dominik Wosiński <wo...@gmail.com> napisał(a):
>
>> Hey, thanks for the answer.
>>
>> But if I add the *AfterMatchSkipStrategy* it simply seems to emit event
>> by event so in the case described above it does emit: [400], [500]
>> Shouldn't the *greedy* quantifier guarantee that this will be matched as
>> many times as possible thus creating [400, 500] ??
>>
>> Thanks again.
>> Best Regards,
>> Dom.
>>

Re: Flink CEP greedy match of single pattern

Posted by Dominik Wosiński <wo...@gmail.com>.

P.S.
So now my pattern looks like this:

Pattern.begin[AccelVector](EventPatternName,
AfterMatchSkipStrategy.skipPastLastEvent())
  .where(_.data() > Threshold)
  .oneOrMore
  .greedy
  .consecutive()
  .within(Time.minutes(1))


śr., 25 mar 2020 o 10:03 Dominik Wosiński <wo...@gmail.com> napisał(a):

> Hey, thanks for the answer.
>
> But if I add the *AfterMatchSkipStrategy* it simply seems to emit event
> by event so in the case described above it does emit: [400], [500]
> Shouldn't the *greedy* quantifier guarantee that this will be matched as
> many times as possible thus creating [400, 500] ??
>
> Thanks again.
> Best Regards,
> Dom.
>