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Guillaume V avatar image
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Guillaume V asked Guillaume V commented

Pull from List not fulfilled but should be

Hello,

On the model that I attach, at ~9000seconds, the model gets stuck due to:
A Pull From List activity doesn't fulfill its activity because it doesn't find what it is looking for.

The problem is that:
It should fulfill its activity as the query in the Pull From List is" WHERE ParentID = puller.ParentID". and both the puller and the token in the list at the time have ParentID = 1.


I have tried a lot of problem-solving techniques but I am unable to understand the reason why my pull from activity doesn't fulfill the request.


INFORMATION:

Pull From List = "Remove ParentID from PREPREP"
List = "NestsPrePrep"
Time = ~9000seconds

Screenshot =1631006431670.png


Model = NotPullingFromListProperlyAt9000s.fsm

FlexSim 19.0.0
processflowlistflexsim 19.0.0pull from listprocess flow pull from list
5 |100000

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1 Answer

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Felix Möhlmann avatar image
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Felix Möhlmann answered Guillaume V commented

This happens due to a timing collision with your other check whether there are entries on the list.

The tokens there try to pull the same entry from the list. Yes, the activity is set to "Leave entries on list", but both "Pull from List" activities happen simultaneously. So one of the "check"-tokens might pull the value and before it is made available again, the pull from the token further down was unsuccessful. It then doesn't get evaluated again, because no new entry gets added to the list.

The probability of this happening increases with more tokens trying to pull at the same time, which is probably why it only happens later on in the run.

The solution is to place a zero-second delay (the devs call these "Breathe", so I stick with that) after the wait for event activity. Now, the token further down gets to try to pull the value first, before the "check"-tokens get to go.

1631010593529.png

(Or you change the setting in the wait for event to "Increase to or through value" and skip the pull from list, as you then know that there are entries on the list)

notpullingfromlistproperlyat9000s_fm.fsm


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Guillaume V avatar image Guillaume V commented ·
Thanks, @Felix Möhlmann

I didn't know this concept. Thank you for your clear explanation.

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