Simultaneous Delete Item Trigger Flows

[tsyrell]

I am looking for some help/thoughts on how to manage simultaneous flows executing from delete item triggers.  I have a primary SharePoint list that contains design information at the design id and design step level.  I have a flow that automatically updates the step number when a new item is added for the design id.  I have a secondary SP list that maintains the 'last' design step number for each design id.

I've created a flow with a delete item trigger that will re-sequence the remaining design steps, and update the secondary SP list with the new last step number.  Works great on individual deletes.  The problem is when the user deletes multiple rows for the same design id.  This kicks off multiple flows, which then result in data conflicts trying to re-sequence the design steps.

Is there any way to have a flow wait until a previous iteration of it has completed?

Thanks!

[v-yamao-msft]

Hi @tsyrell ,

It’s a default behavior that if multiple items are updated/deleted at the same time, flow will be triggered for each modification/deletion at the same time.

For your scenario, please try to turn off Split on to see if it will work for you. With the Split on turned off, if user deleted multiple items at the same, flow will only be triggered one time, which then won’t result in a conflict error.

Please check the following doc on Split on for more details:

https://flow.microsoft.com/en-us/blog/four-connector-action-settings/

Best regards,

Mabel

[tsyrell · Accepted solution]

Thanks Mabel, 

That didn't quite do the trick, but actually led me to the answer.  When I turned Split off, the flow wanted to load all of the impacted items into an array, and I would have had to modify the flow to handle the array of items rather than a single item.  What I did see in the trigger settings was a setting for Concurrency Control, which I turned on and set the Degree of Parallelism to 1.  This set the maximum number of iterations of the flow that could execute simultaneously to 1.  

When I then attempted to delete multiple items, although multiple flows were triggered, all but the first flow were in a 'waiting' status, with each one waiting until the one before it completed.  This gave me exactly what I needed.

Thanks for pointing me in the right direction!

Tom