[jboss-jira] [JBoss JIRA] (DROOLS-997) Events that have already expired when inserted may trigger rules before expiring

[Edson Tirelli (JIRA)]

    [ https://issues.jboss.org/browse/DROOLS-997?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13153173#comment-13153173 ] 

Edson Tirelli commented on DROOLS-997:
--------------------------------------

[~cpitman] the engine doesn't have enough information to know if an expired event is expected do be dropped (because it is no longer relevant on the use case) or processed to avoid the loss of events (due, for instance, to a network delay, or a server down, etc). Please note that we are talking about millisecond time resolution here. It is "easy" to understand the use case of "the event is three hours late", but what if the event is 1ms late? Should the engine process it or not?

The only possible deterministic behaviour is to process all incoming events, and match them once before expiring.

If on a given deployment, events should be dropped after an arbitrary timespan (for instance, if they are more than 10 seconds late, or more than 1 hour late, etc), then the recommended approach is to simply filter out such events before reaching the engine.
 

> Events that have already expired when inserted may trigger rules before expiring
> --------------------------------------------------------------------------------
>
>                 Key: DROOLS-997
>                 URL: https://issues.jboss.org/browse/DROOLS-997
>             Project: Drools
>          Issue Type: Bug
>          Components: core engine
>    Affects Versions: 6.1.0.Final
>         Environment: BRMS CEP 6.1.3 GA
>            Reporter: Chris Pitman
>            Assignee: Mario Fusco
>              Labels: fusion
>
> Events that have already expired when they are inserted have their expiration times changed to the insertion time, which will not expire until the clock ticks at least once.
> Isee the following in `drools-core/src/main/java/org/drools/core/phreak/PropagationEntry.java`:
> {code:java}
> long effectiveEnd = eventFactHandle.getEndTimestamp() + expirationOffset;
> long nextTimestamp = Math.max( insertionTime,
>                                     effectiveEnd >= 0 ? effectiveEnd : Long.MAX_VALUE );
>  if (nextTimestamp < workingMemory.getTimerService().getCurrentTime())
> {code}
> So if current time is still insertion time, the event is not expired.



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