I have a page with a class behind that searches the database for all related leads, contacts, accounts, opportunities, and tasks. The search term is the domain, which I match to the email address or the website. We have millions of records and the page works but it takes a really long time to load. What can I do to speed this up? Should I try paginating my queries? Any other ideas?
 

public class domainSearchPage {
    ApexPages.StandardSetController setCont;
    public domainSearchPage(ApexPages.StandardSetController controllerD) {
        setCont = controllerD;
    }
    public String domain {get;set;}
    transient List<Lead> leadList {get;set;}
    transient Set<Id> leadSet {get;set;}
    public Integer leadSize {get;set;}
    transient List<Lead> matchedLeads {get;set;}
    public List<Lead> leadList1K {get;set;}
    public List<Account> accList1K {get;set;}
    public List<Contact> conList1K {get;set;}
    public List<Task> existingTasks1K {get;set;}
    public List<Task> openTasks1K {get;set;}
    transient List<Account> accList {get;set;}
    transient Set<Id> accSet {get;set;}
    public Integer accSize {get;set;}
    transient List<Contact> conList {get;set;}
    transient Set<Id> conSet {get;set;}
    public Integer conSize {get;set;}
    transient List<Opportunity> oppList {get;set;}
    transient Set<Id> oppSet {get;set;}
    public Integer oppSize {get;set;}
    transient List<Task> taskList {get;set;}
    transient Set<Id> taskSet {get;set;}
    transient Set<Id> existingTaskSet {get;set;}
    transient Set<Id> openTaskSet {get;set;}
    public Integer openTaskSize {get;set;}
    public List<Task> openTasks {get;set;}
    public List<Task> existingTasks {get;set;}
    public Integer existingTaskSize {get;set;}
    transient Set<Id> whoSet {get;set;}
    transient Set<Id> whatSet {get;set;}
    transient Set<Id> repSet {get;set;}
    public Integer repSize {get;set;}
    public List<Lead> leadShortList {get;set;}
    public List<Contact> conShortList {get;set;}
    public List<Task> openTaskShortList {get;set;}
    public List<Task> existingTaskShortList {get;set;}
    public List<Account> accShortList {get;set;}
    public List<Opportunity> oppShortList {get;set;}
    public List<Opportunity> oppListTest {get;set;}
    public List<OpportunityContactRole> ocrList {get;set;}
    
    public void search(){
        if(Test.isRunningTest()){domain='test';}
        leadSet= new Set<Id>();
        conSet = new Set<Id>();
        accSet = new Set<Id>();
        oppSet = new Set<Id>();
        taskSet = new Set<Id>();
        whoSet = new Set<Id>();
        whatSet = new Set<Id>();
        existingTaskSet = new Set<Id>();
        openTaskSet = new Set<Id>();
        repSet = new Set<Id>();
        
        leadList = new List<Lead>();
        matchedLeads = new List<Lead>();
        conList = new List<Contact>();
        oppList = new List<Opportunity>();
        ocrList = new List<OpportunityContactRole>();
        oppShortList= new List<Opportunity>();
        conShortList = new List<Contact>();
        accShortList = new List<Account>();
        leadShortList = new List<Lead>();
        existingTaskShortList = new List<Task>();
        openTaskShortList = new List<Task>();
        existingTasks= new List<Task>();
        openTasks= new List<Task>();

        leadList = new List<Lead>();
        conList=new List<Contact>();
        existingTasks=new List<Task>();
        openTasks=new List<Task>();
        accList=new List<Account>();
        oppList=new List<Opportunity>();
        oppShortList=new List<Opportunity>();
        
        //get list of users for task search later
        List<User> repList = new List<User>([SELECT Id FROM User WHERE Forecast_User__c=TRUE]);
        List<User> notSales = new List<User>([SELECT Id FROM User WHERE Forecast_User__c=FALSE]);
		Set<Id> notSalesSet = new Set<Id>();
        for(User u :notSales){
            notSalesSet.add(u.Id);
        }
        Set<Id> repSet = new Set<Id>();
        Set<Id> salesReps = new Set<Id>();
        for(User u :repList){
            salesReps.add(u.Id);
        }
        String leadQuery = 'SELECT Id,Name,Domain__c,Part_of_Prospecting_List__c,Territory_ID__c,Company_Size__c,Matched_Account__c,Matched_Account__r.Name,Matched_Account__r.OwnerId,Website,OwnerId,Owner.Name,Owner.UserRole.Name,Company FROM Lead where IsConverted=FALSE AND (Part_of_Prospecting_List__c=TRUE OR Synced_with_HubSpot__c=TRUE) AND Domain__c LIKE \''+domain+'%\'';
        leadList = Database.query(leadQuery);
        system.debug('leadList '+leadList.size());
        for(Lead l :leadList){
            leadSet.add(l.Id);
            whoSet.add(l.Id);
            repSet.add(l.OwnerId);
        }
        String leadsWebsite = 'SELECT Id,Name,Domain__c,Part_of_Prospecting_List__c,Territory_ID__c,Company_Size__c,Matched_Account__c,Matched_Account__r.Name,Matched_Account__r.OwnerId,Website,OwnerId,Owner.Name,Owner.UserRole.Name,Company FROM Lead where IsConverted=FALSE AND (Part_of_Prospecting_List__c=TRUE OR Synced_with_HubSpot__c=TRUE) AND Website LIKE \''+domain+'%\'';
        List<Lead> leadListWebsite = new List<Lead>();
        leadListWebsite = Database.query(leadsWebsite);
        system.debug('leadListWebsite '+leadListWebsite.size());
        for(Lead l :leadListWebsite){
            leadSet.add(l.Id);
            whoSet.add(l.Id);
            repSet.add(l.OwnerId);
        }
        system.debug('repSet '+repSet);
        String leadsLMdomain = 'SELECT Id,Name,Domain__c,Part_of_Prospecting_List__c,Territory_ID__c,Company_Size__c,Matched_Account__c,Matched_Account__r.Name,Matched_Account__r.OwnerId,Website,OwnerId,Owner.Name,Owner.UserRole.Name,Company FROM Lead where IsConverted=FALSE AND (Part_of_Prospecting_List__c=TRUE OR Synced_with_HubSpot__c=TRUE) AND Matched_Account__r.Domain_for_lead_conversion__c LIKE \''+domain+'%\'';
        List<Lead> leadListLMdomain = new List<Lead>();
        leadListLMdomain = Database.query(leadsLMdomain);
        system.debug('leadListLMdomain '+leadListLMdomain.size());
        for(Lead l :leadListLMdomain){
            leadSet.add(l.Id);
            whoSet.add(l.Id);
            repSet.add(l.OwnerId);
        }
        String leadsLMwebsite = 'SELECT Id,Name,Domain__c,Part_of_Prospecting_List__c,Territory_ID__c,Company_Size__c,Matched_Account__c,Matched_Account__r.Name,Matched_Account__r.OwnerId,Website,OwnerId,Owner.Name,Owner.UserRole.Name,Company FROM Lead where IsConverted=FALSE AND (Part_of_Prospecting_List__c=TRUE OR Synced_with_HubSpot__c=TRUE) AND Matched_Account__r.Website LIKE \''+domain+'%\'';
        List<Lead> leadListLMwebsite = new List<Lead>();
        leadListWebsite = Database.query(leadsLMwebsite);
        system.debug('leadListLMWebsite '+leadListLMWebsite.size());
        for(Lead l :leadListLMwebsite){
            leadSet.add(l.Id);
            whoSet.add(l.Id);
            repSet.add(l.OwnerId);
        }
        system.debug('repSet '+repSet);
        List<Lead> getRelated = new List<Lead>([SELECT Id, Matched_Account__c,Matched_Account__r.Name,Matched_Account__r.OwnerId FROM Lead WHERE Id IN :leadSet]);
        for(Lead l :getRelated){
            repSet.add(l.Matched_Account__r.OwnerId);
            accSet.add(l.Matched_Account__c);
        }

        leadSize=leadSet.size();

        String accQuery = 'SELECT Id,OwnerId,Name,Owner.UserRole.Name,Owner.Name,Territory_ID__c,Company_Size__c,Website,Domain_for_lead_conversion__c FROM Account WHERE Domain_for_lead_conversion__c LIKE \''+domain+'%\'';
        accList = Database.query(accQuery);
        for(Account a :accList){
            accSet.add(a.Id);
            repSet.add(a.OwnerId);
        }

        String accWebsite = 'SELECT Id,OwnerId,Name,Owner.UserRole.Name,Owner.Name,Territory_ID__c,Company_Size__c,Website,Domain_for_lead_conversion__c FROM Account WHERE Website_Domain__c LIKE \''+domain+'%\'';
        List<Account> accWebsiteList = Database.query(accWebsite);
        for(Account a :accWebsiteList){
            accSet.add(a.Id);
            repSet.add(a.OwnerId);
        }
        accSize=accSet.size();

        String conQuery = 'SELECT Id,AccountId,OwnerId,Account.Name,Name,Owner.Name,Owner.UserRole.Name,Domain__c FROM Contact WHERE Domain__c LIKE \'%'+domain+'%\'';
        conList = Database.query(conQuery);
        for(Contact c :conList){
            conSet.add(c.Id);
            whoSet.add(c.Id);
        }

        ocrList = new List<OpportunityContactRole>([SELECT Id,ContactId,Contact.OwnerId,Opportunity.OwnerId,OpportunityId FROM OpportunityContactRole WHERE ContactId IN :accSet]);
            for(OpportunityContactRole ocr :ocrList){
                conSet.add(ocr.ContactId);
                whoSet.add(ocr.ContactId);
                whatSet.add(ocr.OpportunityId);
                repSet.add(ocr.Opportunity.OwnerId);
            }
        conSize=conSet.size();
            oppList = new List<Opportunity>([SELECT Id,Name,Account.Name,AccountId,Amount,CloseDate,Territory_ID__c,Company_Size__c,OwnerId,Owner.Name,Owner.UserRole.Name,Type FROM Opportunity 
                                             WHERE CloseDate>=TODAY AND IsClosed=FALSE AND AccountId IN :accSet]);
            for(Opportunity o :oppList){
                oppSet.add(o.Id);
                whatSet.add(o.Id);
                repSet.add(o.OwnerId);
            }

        //find related tasks
        openTasks = new List<Task>([SELECT Id,OwnerId,Owner.Name,Owner.UserRole.Name,ActivityDate,Type,Subject,Who.Name,What.Name,WhoId,WhatId FROM Task 
            WHERE OwnerId IN :repSet AND (WhoId IN :whoSet OR WhatId IN :whatSet) AND ActivityDate>=TODAY AND Status !='Completed' AND (NOT Subject LIKE '%Automated%') AND (Type LIKE 'Call%' OR Type LIKE 'Email%' OR Type = 'Follow up') ORDER BY ActivityDate LIMIT 50]);

        for(Task t :openTasks){
            repSet.add(t.OwnerId);
            openTaskSet.add(t.Id);
        }
        existingTasks = new List<Task>([SELECT Id,OwnerId,Owner.Name,Owner.UserRole.Name,ActivityDate,Type,Subject,Who.Name,What.Name,WhoId,WhatId FROM Task 
                                        WHERE OwnerId IN :repSet AND (WhoId IN :whoSet OR WhatId IN :whatSet) AND ActivityDate<=TODAY AND ActivityDate>=LAST_N_DAYS:120 AND Status ='Completed' AND (Type LIKE 'Call%' OR Type LIKE 'Email%' OR Type = 'Follow up') ORDER BY ActivityDate LIMIT 50]);

        if(existingTasks.size()!=0){
            for(Task t :existingTasks){
                repSet.add(t.OwnerId);
                existingTaskSet.add(t.Id);
            }
        }
        
        accSet.remove(null);
        repSet.remove(null);
        repSet.removeAll(notSalesSet);
        repSize=repSet.size();
        oppSize=oppSet.size();
        accSize=accSet.size();


        //short lists
        conShortList = new List<Contact>([SELECT Id,AccountId,OwnerId,Account.Name,Name,Owner.Name,Owner.UserRole.Name,Domain__c FROM Contact WHERE ID IN :conSet ORDER BY LastModifiedDate DESC LIMIT 5]);
        conList1K = new List<Contact>([SELECT Id,AccountId,OwnerId,Account.Name,Name,Owner.Name,Owner.UserRole.Name,Domain__c FROM Contact WHERE ID IN :conSet ORDER BY LastModifiedDate DESC LIMIT 999]);
        oppShortList = new List<Opportunity>([SELECT Id,Name,Account.Name,AccountId,Amount,CloseDate,Territory_ID__c,Company_Size__c,OwnerId,Owner.Name,Owner.UserRole.Name,Type FROM Opportunity WHERE ID IN :oppSet ORDER BY CloseDate ASC LIMIT 5]);
        existingTaskShortList = new List<Task>([SELECT Id,OwnerId,Owner.Name,Owner.UserRole.Name,ActivityDate,Type,Subject,Who.Name,What.Name,WhoId,WhatId FROM Task 
                                                WHERE OwnerId IN :repSet AND (WhoId IN :whoSet OR WhatId IN :whatSet) AND ActivityDate<=TODAY AND ActivityDate>=LAST_N_DAYS:120 AND Status ='Completed' AND (Type LIKE 'Call%' OR Type LIKE 'Email%' OR Type = 'Follow up') ORDER BY ActivityDate DESC LIMIT 5]);
        existingTasks1K = new List<Task>([SELECT Id,OwnerId,Owner.Name,Owner.UserRole.Name,ActivityDate,Type,Subject,Who.Name,What.Name,WhoId,WhatId FROM Task 
                                          WHERE OwnerId IN :repSet AND (WhoId IN :whoSet OR WhatId IN :whatSet) AND ActivityDate<=TODAY AND ActivityDate>=LAST_N_DAYS:120 AND Status ='Completed' AND (Type LIKE 'Call%' OR Type LIKE 'Email%' OR Type = 'Follow up') ORDER BY ActivityDate DESC LIMIT 999]);
        openTaskShortList = new List<Task>([SELECT Id,OwnerId,Owner.Name,Owner.UserRole.Name,ActivityDate,Type,Subject,Who.Name,What.Name,WhoId,WhatId FROM Task 
                                            WHERE OwnerId IN :repSet AND (WhoId IN :whoSet OR WhatId IN :whatSet) AND ActivityDate>=TODAY AND Status !='Completed' AND (NOT Subject LIKE '%Automated%') AND (Type LIKE 'Call%' OR Type LIKE 'Email%' OR Type = 'Follow up') ORDER BY LastModifiedDate DESC LIMIT 5]);
        openTasks1K = new List<Task>([SELECT Id,OwnerId,Owner.Name,Owner.UserRole.Name,ActivityDate,Type,Subject,Who.Name,What.Name,WhoId,WhatId FROM Task 
                                      WHERE OwnerId IN :repSet AND (WhoId IN :whoSet OR WhatId IN :whatSet) AND ActivityDate>=TODAY AND Status !='Completed' AND (NOT Subject LIKE '%Automated%') AND (Type LIKE 'Call%' OR Type LIKE 'Email%' OR Type = 'Follow up') ORDER BY ActivityDate DESC LIMIT 999]);
        leadShortList = new List<Lead>([SELECT Id,Name,Company,Domain__c,Website,Territory_ID__c,Company_Size__c,Part_of_Prospecting_List__c,Matched_Account__c,Matched_Account__r.Name,OwnerId,Owner.Name,Owner.UserRole.Name FROM Lead WHERE Id IN :leadSet ORDER BY LastModifiedDate DESC LIMIT 5]);
        leadList1K = new List<Lead>([SELECT Id,Name,Company,Domain__c,Website,Territory_ID__c,Company_Size__c,Part_of_Prospecting_List__c,Matched_Account__c,Matched_Account__r.Name,OwnerId,Owner.Name,Owner.UserRole.Name FROM Lead WHERE Id IN :leadSet ORDER BY LastModifiedDate DESC LIMIT 999]);
        accShortList = new List<Account>([SELECT Id,OwnerId,Name,Owner.UserRole.Name,Owner.Name,Territory_ID__c,Company_Size__c,Website,Domain_for_lead_conversion__c FROM Account WHERE ID IN :accSet ORDER BY LastModifiedDate DESC LIMIT 5]);
        accList1K = new List<Account>([SELECT Id,OwnerId,Name,Owner.UserRole.Name,Owner.Name,Territory_ID__c,Company_Size__c,Website,Domain_for_lead_conversion__c FROM Account WHERE ID IN :accSet ORDER BY LastModifiedDate DESC LIMIT 999]);
        existingTaskSize=existingTasks1K.size();
        openTaskSize=openTasks1K.size();
    }
        public pageReference clear(){
        leadList.clear();
            return null;
    }
    
    //method for Show More (leads)
    public pageReference showMore(){
        PageReference leadPage = new PageReference('/apex/showMore');
        return leadPage;
    }
        //method for Show More (Contacts)
    public pageReference showMoreContacts(){
        PageReference conPage = new PageReference('/apex/showMoreContacts');
        return conPage;
    }
        //method for Show More (Accounts)
    public pageReference showMoreAccounts(){
        PageReference conPage = new PageReference('/apex/showMoreAccounts');
        return conPage;
    }
            //method for Show More (open tasks)
    public pageReference showMoreOpenTasks(){
        PageReference openPage = new PageReference('/apex/showMoreOpenTasks');
        return openPage;
    }
            //method for Show More (existing tasks)
    public pageReference showMoreExistingTasks(){
        PageReference exPage = new PageReference('/apex/showMoreExistingTasks');
        return exPage;
    }    
}