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Question

Workflow Tasks and their Order of Operations

asked on August 24, 2018 Show version history

We have been debugging a situation where a workflow step failed.  This rule has a mix of long running and short running tasks, ranging from a Get Metadata task at 33 ms to a SQL update at 1 sec 500 ms.  As we looked at the actual task details we noticed that some of our early tasks were not finished before some of the later tasks had begun.  Here is a simplified example:

Task A:  Starts at 7:15:10 AM, ends at 7:15:12 AM

Task B:  Starts at 7:15:11 AM, ends at 7:15:11 AM

Task B started before Task A was finished.

In another case, we had a task that posts a row, and then a task right after that reads it.  The second task failed (no results) yet the row was present when we checked.

I assumed each rule instance has its own thread, but it also looks like each task has its own thread.  However, in a linear product like Workflow, it's hard to see how it would work unless is is sequential.  So, is this just an issue with the reporting, or should we be adding a delay after each long running task?

It feels very quantum...

 

 

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Replies

replied on August 24, 2018

Assuming those tasks were sequential, that might just be a slight time discrepancy between your SQL and WF server (one of the value is set using WF's time, the other using SQL time).

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replied on August 30, 2018

Hi Miruna - The tasks were sequential, and I'll take your answer to mean that Workflow does in fact execute tasks in a sequential manner, just the way you would expect.  The only issue with the time difference theory is that if the servers were out of synchronization, you could expect the time difference to always be the same amount.

Looking at the actual data, that is not the case. By and large, the start and stop times are the same.  But looking at the ones in bold, there is a difference as large as :02.  I can assure you that neither server was traveling close to the speed or light, nor where they near any black holes, as far as I can tell.

Start Time                  Stop Time

8/3/2018 6:55:17.0     8/3/2018 7:00:30.0

8/3/2018 7:00:30.0     8/3/2018 7:00:30.0

8/3/2018 7:00:30.0     8/3/2018 7:00:30.0

8/3/2018 7:00:30.0     8/3/2018 7:00:30.0

8/3/2018 7:00:30.0     8/3/2018 7:00:32.0

8/3/2018 7:00:30.0     8/3/2018 7:00:32.0

8/3/2018 7:00:30.0     8/3/2018 7:00:31.0

8/3/2018 7:00:31.0     8/3/2018 7:00:32.0

8/3/2018 7:00:31.0     8/3/2018 7:00:32.0

8/3/2018 7:00:32.0     8/3/2018 7:00:32.0

8/3/2018 7:00:32.0     8/3/2018 7:00:32.0

8/3/2018 7:00:32.0     8/3/2018 7:00:34.0

8/3/2018 7:00:32.0     8/3/2018 7:00:34.0

8/3/2018 7:00:33.0     8/3/2018 7:00:34.0

8/3/2018 7:00:33.0     8/3/2018 7:00:33.0

8/3/2018 7:00:33.0     8/3/2018 7:00:33.0

 

 

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replied on August 31, 2018

I'm not really sure what I'm looking at here, but it's worth more digging. Can you take it to Tech Support, though, so we can take a closer look?

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replied on August 31, 2018 Show version history

Hi Miruna - that is a list of the start and stop times for all of the tasks in one of our rules, sorted by their start times.  RE: Support, I can keep you posted as to what we find, thanks.  Bill

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