I wrote a batch apex that implements Database.Batchable class. I am using a AggregateResult query on execute method for sum and count etc. Is there any chance of hitting governor limit if my no of records are around 1/2 lakhs and batch size is 200. Actually I came to know , that AggregateResult counts against the no of rows processed during calculation and not on the no of rows returned. Kindly let me know if there is any alternative. Thanks. Sample Code is added here -

  global class sample_BATCH implements Database.Batchable<sObject> {
global Database.QueryLocator start(Database.BatchableContext BC) 
  Set<Id> rtId = new Set<Id>();
  String rtName = 'xxx;
  for (RecordType rt : [select id, Name  from RecordType where name = : rtName])
 //master obj
  String query = 'SELECT Id, recordtypeid, Name, End_Date__c,start_Date__c FROM Survey__c WHERE recordtypeid IN : rtId ';
  return Database.getQueryLocator(query);  

global void execute(Database.BatchableContext BC, List<Survey__c> scope) 
  Decimal rs1 =0.0;                   
  Decimal rs2 = 0.0;
  Decimal rs3 = 0.0;
// detail obj
  List <Survey_Target__c> updSRTlst = new List <Survey_Target__c>();
// this query may have ~ 50k record per scope i.e for each master record id.
  Map<id,List<Decimal>> sTgtToSurvMap = new Map<id,List<Decimal>> ();
  AggregateResult[] sg= [SELECT Survey__c, SUM(r_1__c) Res1, SUM(r_2__c) Res2 ,COUNT(id) Res3 FROM Survey_Target__c  where Survey__c  in : scope 
                             AND Status__c = 'Submitted_a' GROUP BY Survey__c];   

  List <Decimal> r1List = new List <Decimal>();
  List <Decimal> r2List = new List <Decimal>();

  Decimal r1 = 0.0;
  Decimal r2 = 0.0;
  Decimal r3 = 0.0;
  for (Sobject sObj : sg)
      r1 = (Decimal) (sObj.get('Res1'));    
      r2 = (Decimal) (sObj.get('Res2'));       
      r3 = (Decimal) (sObj.get('Res3'));                           
      List <Decimal> reslst = new List <Decimal>();
      if (reslst == null ||  reslst.isEmpty())
      //stores master record is and cut off values from Agg Res query
 //my detail obj
  List <Survey_Target__c> stList= new List <Survey_Target__c>([select id, name,Survey__c r_1__c, r_2__c,End_Date__c,start_Date__c from Survey_Target__c 
                                                                      where Survey__c  in : scope and Status__c = 'Submitted_a' order by survey__c asc,r_1__c desc]);
  for (Survey_Target_vod__c stg : stList)
    // final DML will be done here based on some logic on map.
  • 1/2 lakhs is 50,000 right?
    – Keith C
    Commented Jul 1, 2015 at 9:12
  • @ Hi Keith - yes..its 50k..Actually. In start method I m quering master object ..and within execute doing DML on detail object..for each master record, I can have around 50 k records after using filter critera. So, is there any alternative to skip ths? Also, please note I am using AggregateResult to sum up values from Detail record in a field in the master. I read somwhere that @readonly can be used in schedular class to avoid hitting the governore limit. Is that correct?
    – CRM Guy
    Commented Jul 1, 2015 at 10:21
  • @KeithC - The requirement is to capture Survey Responses from Institutions/Accounts ...so , there could be many detail record (account) tagged to a particular Survey.
    – CRM Guy
    Commented Jul 1, 2015 at 10:27
  • Never new about @ReadOnly on Schedulable. As you can't also do DML I'm not sure how that will help but perhaps there is a way around that.
    – Keith C
    Commented Jul 1, 2015 at 10:34
  • 1
    OK then there is the possibility that if more than 50,000 Survey_Target__c objects are being grouped that you will hit the governor limit. But as you have the code I suggest you try it (you can leave out the DML part) and see - I think there are some query patterns (not documented) that don't enforce that limit.
    – Keith C
    Commented Jul 2, 2015 at 7:12

1 Answer 1


With 50 master records each of which can have > 50,000 child records, running the batchable over the child records may make sense. The code would look something like this:

public class MyBatchable implements Database.Batchable<SObject>, Database.Stateful {

    private Map<Id, Parent__c> parents = new Map<Id, Parent__c>();

    public Database.QueryLocator start(Database.BatchableContext context) {
        return Database.getQueryLocator([
                select Parent__c, Amount__c, ...
                from Child__c

    public void execute(Database.BatchableContext context, List<Child__c> scope) {
        for (Child__c c : scope) {
            Parent__c p = parents.get(c.Parent__c);
            if (p == null) {
                p = new Parent__c(Id = c.Parent__c);
                parents.put(c.ParentId, p);
            p.Sum__c = add(p.Sum__c, c.Amount__c);

    public void finish(Database.BatchableContext context) {
        update parents.values();

    private Decimal add(Decimal a, Decimal b) {
        if (a != null && b != null) return a + b;
        else if (a != null) return a;
        else if (b != null) return b;
        else return null;

and then execute with the maximum batch size of 2,000.

  • Even if the parent records are more than 10K then we can restart the batch. Need to mark parent records in update so that next batch will filter out such records. Nice pattern. Commented Sep 18, 2016 at 4:39

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