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RE: Congratulations on Christian's and co. courage

From: Alex Kozlenkov <alex.kozlenkov@betfair.com>
Date: Wed, 3 Sep 2008 21:44:04 +0100
Message-ID: <E39E50172D7A6546BCE3E981C985C98731EED565@UKMAIL.sportex.com>
To: "Paul Vincent" <pvincent@tibco.com>
Cc: <public-rif-wg@w3.org>

What happens if the duplicate events A;A are truly different, with
different timestamps, and we want this sequence to invalidate a simple
C<=AB pattern? The rule happily emitting two detections given the input
A;A;B may be something entirely incorrect.

-----Original Message-----
From: Paul Vincent [mailto:pvincent@tibco.com] 
Sent: 03 September 2008 20:48
To: Alex Kozlenkov
Cc: public-rif-wg@w3.org
Subject: RE: Congratulations on Christian's and co. courage
Importance: Low

As this qu is CEP-related, I guess I should give an answer too.

1. Gary is correct from the logical perspective, of course.

2. Events can be duplicates either in their transmission or their
meaning:

In middleware terms, it is normally the responsibility of the middleware
to ensure duplicates don't happen! 

In event terms, though, I can receive multiple events which signify the
same information. For example I may be polling a hardware device and
getting the same result, or someone may hit the "Buy" button in their
web browser twice. 

In the latter case, there are 2 order events but they represent the same
order, so there might be some rules / logic in the system to handle this
(de-dupe). Those rules could presumably be represented in RIF, e.g.

If ?BetA and ?BetB occur within 5 secs of each other AND sameContent(
?BetA, ?BetB)
Then // assume BetB is a dupe
?BetB.dupe = TRUE, ?BetB.IsDupeOf = ?BetA, ?BetB.Status = invalid.

...

Paul Vincent
TIBCO | Business Optimization | Business Rules & CEP
 

> -----Original Message-----
> From: public-rif-wg-request@w3.org
[mailto:public-rif-wg-request@w3.org]
> On Behalf Of Gary Hallmark
> Sent: 03 September 2008 18:31
> To: Alex Kozlenkov
> Cc: public-rif-wg@w3.org
> Subject: Re: Congratulations on Christian's and co. courage
> 
> 
> no such thing as 2 identical facts.  Relations are sets.  Frames have
a
> unique OID.
> Note that PRD currently has no way to create a new object, and that is
a
> problem we need to fix.
> 
> Alex Kozlenkov wrote:
> > And one more comment about the minimality I'm discussing in my
previous
> > post. This is not an idle question. If there exist two identical
facts,
> > will there be two actions executed or only one? In the language
dialect
> > for event processing that the JBoss guys are developing, I was
trying to
> > understand whether A<=B,C given B and C matching incoming events, if
C
> > was detected twice, would the action A be executed twice? What I
mean is
> > that there may be situation when we want to only detect one
situation so
> > that the sequence of events CCB should execute A only once.
> >
> >
> >
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> >
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> >
> >


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Received on Wednesday, 3 September 2008 20:45:18 GMT

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