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https://issues.apache.org/jira/browse/FLINK-7169?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16085637#comment-16085637
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Dian Fu commented on FLINK-7169:
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Hi [~ychen],
Thanks a lot working on this ticket. :)
For the API change, may be it's better to add an API in {{Pattern}}, such as
{{Pattern.setSkipStrategy(AfterMatchSkipStrategy afterMatchSkipStrategy)}}.
For the implementation of the {{AfterMatchSkipStrategy}}, I have a very rough
though. For example, for pattern {{a b*}}, if the skip strategy is {{AFTER
MATCH SKIP TO FIST b}}, we only add a new {{Start}} {{ComputationState}} once
the first {{b}} is matched (Not add a new {{Start}} {{ComputationState}} once
the {{Start}} {{ComputationState}} is matched which is the current strategy).
If this is feasible, we don't need to keep track of the event order any more.
Thoughts?
> Support AFTER MATCH SKIP function in CEP library API
> ----------------------------------------------------
>
> Key: FLINK-7169
> URL: https://issues.apache.org/jira/browse/FLINK-7169
> Project: Flink
> Issue Type: Sub-task
> Components: CEP
> Reporter: Yueting Chen
> Assignee: Yueting Chen
>
> In order to support Oracle's MATCH_RECOGNIZE on top of the CEP library, we
> need to support AFTER MATCH SKIP function in CEP API.
> There're four options in AFTER MATCH SKIP, listed as follows:
> 1. AFTER MATCH SKIP TO NEXT ROW: resume pattern matching at the row after the
> first row of the current match.
> 2. AFTER MATCH SKIP PAST LAST ROW: resume pattern matching at the next row
> after the last row of the current match.
> 3. AFTER MATCH SKIP TO FIST *RPV*: resume pattern matching at the first row
> that is mapped to the row pattern variable RPV.
> 4. AFTER MATCH SKIP TO LAST *RPV*: resume pattern matching at the last row
> that is mapped to the row pattern variable RPV.
> I think we can introduce a new function to `CEP` class, which takes a new
> parameter as AfterMatchSKipStrategy.
> The new API may looks like this
> {code}
> public static <T> PatternStream<T> pattern(DataStream<T> input, Pattern<T, ?>
> pattern, AfterMatchSkipStrategy afterMatchSkipStrategy)
> {code}
> We can also make `SKIP TO NEXT ROW` as the default option, because that's
> what CEP library behaves currently.
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