I've just written my second trigger and it seems that I'm needing to learn more about how to optimize my code. My trigger runs through the campaign members of a campaign and changes the member status of any email duplicates (but leaves one) so that an email isn't sent twice to one emails. As a nonprofit many of our donors share an email address in their household so we removing the email addresses from the contacts isn't possible. To help with this, I wrote the trigger below. It worked great in testing on a few hundred campaign members but when I tested it on a few thousand I received the dreaded 'System.LimitException: Apex CPU time limit exceeded'.

Could anyone help me optimize this code? I'd love to learn how and apply this knowledge to future triggers.

trigger CleanEmailAddresses on Campaign (after update) {

    for (Campaign camp : Trigger.new) {

        // Check for clean email addresses trigger
        if (camp.clean_emails__c == true) {

            if (camp.IsActive && camp.Status != 'Completed' && camp.Status != 'Aborted') {

            // Counters used later
            Integer uniqueEmailCount = 0;
            Integer dupeCounter = 0;

            // Initialize list that will hold duplicate email addresses
            List<CampaignMember> theseAreTheDupes = new List<CampaignMember>();

            // Check to see if campaign has member status 'Email Duplicate'
            List<CampaignMemberStatus> campaignStatuses = [SELECT Id,
                                                             FROM CampaignMemberStatus
                                                            WHERE CampaignId = :camp.Id AND
                                                                  Label      = 'Email Duplicate'];

            // No? Then create it
            if (campaignStatuses.size() == 0) {

                CampaignMemberStatus newCampaignMemberStatus = new CampaignMemberStatus();
                newCampaignMemberStatus.Label                = 'Email Duplicate';
                newCampaignMemberStatus.CampaignId           = camp.Id;
                insert newCampaignMemberStatus;


            // Create list of email addresses already in campaign that do not have duplicate status
            List<CampaignMember> campaignMembers = [SELECT Id,
                                                      FROM CampaignMember
                                                     WHERE CampaignId   = :camp.Id AND
                                                           Status      != 'Email Duplicate' AND
                                                           HasResponded = false];

            // Initialize string set that will hold list of unique email addresses
            Set<string> uniqueEmails = new Set<string>();

            // Populate set with unique emails
            for (CampaignMember addToUniqueEmailSet : CampaignMembers) {



            // Loop through each unique email address
            for (String uniqueEmailList: uniqueEmails){

                // Loop through email campaign member
                for (Integer i = 0; i < campaignMembers.size(); i++) {

                    // Check to see if current campaign member's email address matches unique address of current iteration
                    if (campaignMembers.get(i).Email == uniqueEmailList) {

                        // Count number of dupes
                        uniqueEmailCount = uniqueEmailCount + 1;

                        // Check to see if duplicate is the first one or note
                        if (uniqueEmailCount > 1) {

                            // If dupe is not the first, add to list of campaign members to change later




                // Reset counter
                uniqueEmailCount = 0;

            system.debug ('dupe list size: '+ theseAreTheDupes.size()); 


            if (theseAreTheDupes.isEmpty() == false) {

                for (CampaignMember cmChangeStatus : theseAreTheDupes) {

                    theseAreTheDupes.get(dupeCounter).Status = 'Email Duplicate';
                    dupeCounter = dupeCounter + 1;


                update theseAreTheDupes;


            } else {

                camp.addError('Whoa there partner! 🐴  Emails can not be cleaned from inactive, aborted or completed campaigns!');




  • You have a few queries in for loops, so even if you resolve the CPU errors this may hit others. That said, this logic may be better moved to a batch/scheduled process. – Adrian Larson May 26 '17 at 16:07

Your main problem is the for-for loop in the middle of the code. As commented, this won't solve all of your problems, but you can drastically reduce CPU time by using a map:

Map<String, List<CampaignMember>> membersByEmail = new Map<String, List<CampaignMember>>();
// Prepopulate map
for(String email: uniqueEmails) {
    membersByEmail.put(email, new CampaignMember[0]);
// Sort into email groups
for(CampaignMember member: campaignMembers) {
for(String email: uniqueEmails) {
    CampaignMember[] emailMembers = membersByEmail.get(email);
    // More than 1 member
    if(emailMembers.size() > 1) {
        // First is not a duplicate
        // The rest of them are
// Update status
for(CampaignMember member: theseAreDupes) {
    member.Status = 'Email Duplicate';
// Commit changes
update theseAreDupes;
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