Hi,

I'm hoping some kind stranger will help me. I copied this trigger from another admin friend but i'm getting an error when i add it to my sandbox. The trigger is suppose to find a potential matching Account from a Lead record based on either the Account Name or a custom Domain field derived from the Account website compared to the email domain on a lead. Here's the code: 

trigger FindDupes on Lead (before insert, before update) {

    // initialize set for SOQL query
    Set<String> emailDomains = New Set<String>();
    Set<String> companyNames = New Set<String>();

    // loop through leads to build sets for lookup
    
        for (Lead myLead : Trigger.new) {
    
            // if lead doesn't have an Account ID
            if (myLead.Account__c == null) {
    
                // if the lead has a company name
                if (myLead.Company != null) {
        
                    // add to set for SOQL query lookup
                    companyNames.add(myLead.Company);
                }
    
                // if the lead has an email domain
                if (myLead.Domain__c != null) {
        
                    // add to set for SOQL query lookup
                    emailDomains.add(myLead.Domain__c);
                }
            
            }
        }
    
    // perform queries and add results to maps
    
        // initialize map of Email Domain to Account
        Map<String, Account> emailToAccountMap = New Map<String, Account>();
    
        // if there are email domains to look up
        if (emailDomains.isEmpty() == false) {
        
            // perform query matching email domains
            List<Account> accounts = [SELECT Id, Domain__c FROM Account
                                      WHERE Domain__c IN :emailDomains];
    
            // if accounts found, add to map
            if (accounts.isEmpty() == false) {
                for (Account a : accounts) {
                    // add to map, key: Email Domain, value: Account
                    emailToAccountMap.put(a.Domain__c, a);
                }
            }   
            
        }
    
        // initialize map of Company Name to Account
        Map<String, Account> nameToAccountMap = New Map<String, Account>();
    
        // if there are company names to look up
        if (companyNames.isEmpty() == false) {
        
            // perform query matching email domains
            List<Account> accounts = [SELECT Id, Name FROM Account
                                      WHERE Name IN :companyNames];
    
            // if accounts found, add to map
            if (accounts.isEmpty() == false) {
                for (Account a : accounts) {
                    // add to map, key: Name, value: Account
                    nameToAccountMap.put(a.Name, a);
                }
            }   
            
        }

    // loop through leads and get results form queries to fill in Account ID
        for (Lead myLead : Trigger.new) {
    
            // if lead doesn't have an Account ID
            if (myLead.Account__c == null) {
        
                // get related Account by Company Name
                Account account1 = nameToAccountMap.get(myLead.Company);
        
                // get related Account by Email Domain
                Account account2 = emailToAccountMap.get(myLead.Domain__c);
            
                // if account found by company name
                if (account1 != null) {
                    myLead.Account__c = account1.Id;

                // if account found by email domain
                } else if (account2 != null) {
                    myLead.Account__c = account2.Id;
                }
            
            
            }
        }

}



I went to try and test the trigger and created a new lead and recieved the following error as soon as i tried to add an email address and save the record (the domain field on Leads is a formula field isolating the domain part of the email address field).


Error: Invalid Data. 
Review all error messages below to correct your data.
Apex trigger FindDupes caused an unexpected exception, contact your administrator: FindDupes: execution of BeforeUpdate caused by: System.QueryException: Non-selective query against large object type (more than 100000 rows). Consider an indexed filter or contact salesforce.com about custom indexing. Even if a field is indexed a filter might still not be selective when: 1. The filter value includes null (for instance binding with a list that contains null) 2. Data skew exists whereby the number of matching rows is very large (for instance, filtering for a particular foreign key value that occurs many times): Trigger.FindDupes: line 40, column 1


Any ideas???? Help!!! 

Thank you in advance!!