Run Apex Code when campaign status is changed to Completed

Question

we would like to run an Apex Code when the user changes the campaign status field to Completed. What is the best way to do that without stressing the system?

I saw it is possible to do it with triggers but I do not want it to run anytime the campaign is updated.

Answer 1

That's literally what triggers are designed for. A trigger that runs but "does nothing" will run in literal milliseconds. Hardly any stress at all. Your code would look like this:

Campaign[] completedCampaigns = new Campaign[0];
for(Integer index = 0; index < Trigger.size; index++) {
  if(Trigger.old[index].Status != Trigger.new[index].Status && Trigger.new[index].Status == 'Completed') {
    completedCampaigns.add(Trigger.new[index]);
  }
}
if(completedCampaigns.size() > 0) {
  YourApexClass.doSomething(completedCampaigns);
}

(Of course, it'd be better as a trigger framework, this is only illustrative).

This code will run in sub-millisecond time if there's only one campaign being updated and it doesn't match the criteria, or about 10-20 ms for 200 records in the list (based on some tests I wrote up to try it out). That's not even 1/10th of one second.

You could also use a Flow with an Apex Action, but realistically, that's overkill for what you're trying to do.