question

Allister Wilson avatar image
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Allister Wilson asked Allister Wilson commented

Batch transport leaving item stuck in upstream queue

In the attached model, the queue batches up 6 items, the TE should then transport 2 batches of 3 items.

Instead it transports 3 items, then 2, leaving the last item stuck in the queue. No task sequence is generated for this item.

Transporting to another queue seems to work, but it fails here to a processor, and also to a sink in the model where our client initially encountered the issue.

This seems to occur regardless of whether the queue's integrated batching is used, or batches are handled manually with open/close commands.

Is there a cleaner workaround than transporting to an intermediate queue until this is fixed?

Edit: For future readers, see Phil Bobo's comments on the accepted answer.

FlexSim 17.0.2
queuebatchtransport
batch-transport.fsm (16.2 KiB)
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1 Answer

Kari Payton avatar image
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Kari Payton answered Allister Wilson commented

@Allister Wilson when I run the model, it appears to run correctly. To check what's going on, make a dashboard chart with the throughput from each object. I see an output of 6 boxes from the queue and 6 boxes through the processor. As soon as the queue clears, after the 6th box, the source creates another object in the queue. That may be why you are seeing another item there.


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Allister Wilson avatar image Allister Wilson commented ·

It appears we are seeing different results then, this is how my model run ends.

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batch-transport.png (66.6 KiB)
Kari Payton avatar image Kari Payton commented ·

@Allister Wilson

on your queue batching properties, un-check "flush contents between batches" and you may be able to see the boxes in the queue as they are created. The flush contents between batches will not allow new flowitems to enter the queue until the entire current batch is left. Also did you create the dashbaords to see the throughput?

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Steven Hamoen avatar image Steven Hamoen Kari Payton commented ·

@Kari Payton,@Allister Wilson

I have the same results as Alister and I also made the dashboard. See picture

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bugqueue.png (134.9 KiB)
Kari Payton avatar image Kari Payton commented ·

That's weird... see model 5504-batch-transport.fsm

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5504-batch-transport.fsm (18.0 KiB)
Allister Wilson avatar image Allister Wilson Kari Payton commented ·

That model doesn't use batch flushing so the issue never shows up, but the interesting part is that deleting the A* and enabling batching doesn't bring the issue back...

Would be great if a developer could shed some light on why these models behave differently / how we can reliably avoid the issue like Kari's model appears to. @Logan Gold @Sam Stubbs

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Allister Wilson avatar image Allister Wilson Allister Wilson commented ·

Could someone take a look at this please?

@anthony.johnson @Matt Long @phil.bobo

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