Update multiple records in trigger-based Flow but only run it once

Question

I'm building a Flow to update sequential values on records.

• Each record (CampaignMember within a Campaign of specific record type) has a numerical "rank" value that can be set manually by a user.
• When a value is changed on one record the Flow updates all the records that need to be changed in order to keep the rankings sequential and prevent duplicates.

So for example, if I set a record's rank to 7 and there are already records with ranks 7, 8, and 9, the existing records should all be incremented by one.

The Flow works, however, since each record is updated the Flow gets triggered again by each subsequent record that is updated. I could modify the Flow to only touch one record at a time but that would be really inefficient.

Currently I load up the other CampaignMember records that need to be updated, loop through them incrementing, or decrementing, their rank and put them into a variable collection that is saved at the end.

What would be nice is if I could only run the Flow when I can detect that the record was not updated by a Flow. Is there a way I can do this so that I can make the updates in bulk?

Answer 1

What you are looking for is some indication of transaction state to control recursion

In an Apex trigger, this would be done with static sete of IDs that you have already visited. But, since you are using Flow, perhaps the following is a robust solution:

Step 1

Create an invocable Apex class that accepts a list of Ids and returns a list of Booleans

static Set<Id> visitedIds = new Set<Id>();
@InvocableMethod
public static List<List<Boolean>> isVisited(List<List<Id>> interviewsIds) {
   List<List<Boolean>> results = new List<List<Boolean>>();
   for (List<Id> interviewIds: interviewsIds) {
      List<Boolean> interviewResults = new List<Boolean>();
      for (Id id: interviewIds){
         if (visitedIds.contains(id)) {
             interviewResults.add(true);
          }
          else {
              interviewResults.add(false);
              visitedIds.add(id);
          }
       }
       results.add(interviewResults);
    }
    return results;
  }
}  

Step 2

Have your Flow use an Apex Action and pass the id collection of records you are considering reranking.

The Apex action will return a collection variable of true/falses in the same order as the id collection and you can loop through those to decide whether to rerank

Example

Initial pass of a flow interview is for Id 7 and you are going to rerank 8,9,10

You pass to the Apex action the Ids for 7-8-9-10 and get back all falses. This tells you can rerank with an Update element

When records 8-9-10 get updated and enter the flow again (same transaction), the flow will invoke the Apex Action again but this time it returns a collection of all falses - so the Flow Interview does no Update and essentially stops

Notes

This solution avoids the timestamp solution you proposed in your comment which would work "most of the time" but edge cases could compromise the 5 minute rule at some point in the future, perhaps long after you are gone from the scene

Note also that because there could be many records running flow interviews, the invocable apex has to be bulkified, hence the List<List> argument