[rules-users] Fusion 5.5 - Deterministically identifying event insert order?

[Wolfgang Laun]

There's no reason why two events shouldn't have identical timestamps.

Having to preserve order in the absence of any other distinction can't be
necessary? Can't you use any other attribute to derive the order?

If you think that you must have different timestamps: why don't you
apply the timestamp yourself and add a tick when the current insert
(of a stream) is still within the same ms.

BTW: You overuse salience. Add logic to  get things done at the proper
time, i.e., according to the proper situation.

-W

On 24/09/2013, dunnlow <dunnlow at yahoo.com> wrote:
> I am testing with fusion (5.5) and running into an /intermittent /issue.  I
> am trying to track transitions between two big events (BEvent) using a
> smaller event (SEvents) with the properties I care about.  The idea is that
> I will maintain many SEvents in memory for the different kinds of BEvents.
> My basic steps (partly driven by salience) are:
>
> 1) rule a:  (salience=100): when a new BEvent is inserted, insert a new
> related SEvent
> 2) rule b: (salience=50): If there are two SEvents for this type of BEvent,
> compare them (old vs new) and act accordingly
> 3) rule c: (salience=0) remove the *old* SEvent (keeping the latest one)
> 4) rule d: (salience=-50) retract the BEvent
>
> My rule c (above) is:
> when $se1 : SEvent(name matches "auto")
>          $se2 : SEvent(this after $se1, style matches ($se1.style))
> then
>    retract($se1);
> end;
>
> I am of course running in stream mode and this USUALLY works, but sometimes
> rule c does not get activated - based on the audit log.  Also, I have a
> DebugWorkingMemoryEventListener configured and I can see that two SEvents
> DO
> exist in working memory which should activate it.
>
> In my test, I have a loop in which I am inserting events.  When I add a
> brief delay, I have not seen a failure.  My guess is that the timestamps on
> the two events are the same, thus the "after" is causing the issue.
> However, I am unable to test this as the timestamp on the event is not
> accessible (from what I have found on this forum).
>
> I saw a suggestion here about using a variable on my SEvent to tell the
> difference between a new and old version.  I also considered using some
> sort
> of counter bean to order the SEvents (although I believe it would need to
> be
> serialized).
>
> My questions:
> 1) Do you agree with my assessment?  Is it possible in stream mode to have
> two events with the same timestamp?
> 2) what is the BEST way to identify which event was inserted first?
>
> Thanks for any insight!
> -J
>
>
>
>
>
> --
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> http://drools.46999.n3.nabble.com/Fusion-5-5-Deterministically-identifying-event-insert-order-tp4026117.html
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