[SalesForce] Question regarding “RunOnce” Booleans on AfterUpdate methods in a Salesforce Transaction

I recently encountered a business logic bug in our org that was accidentally deducting a customer 2x for completing an event that only actually occurred once. Using dev console I was able to determine that the method was running twice as a result of a Workflow Field Update that caused the transaction to loop through the order of execution a second time. Unchecking the "re-evaluate" box on the workflow rule didn't stop the bug.

So, I went the route of creating a 'RunOnce' style Boolean in a Helper Class, checking if it is false at the start of the method, and then setting it to true as the last line in the entire method (even after DML updates). This of course doesn't stop the record(s) from going through order of execution again, but it does stop the method from running since it already ran.

Example with main business logic removed for size purposes:

public static void updateUsedTrainingTimeUsingEventMaps(Map<Id,Event> oldEventMap, Map<Id,Event> newEventMap){
    if(ValidatorClass.UpdateTrainingTimeTriggerFired == false){ // check if this method has run already

        for(Event event : newEventMap.values())
        {
            A BUNCH OF BUSINESS LOGIC, FIELD UPDATES, ADDING TO UPDATE LISTS, ETC
        } // end of for loop

    update accountMap.values();
    ValidatorClass.UpdateTrainingTimeTriggerFired = true; // stop method from running again in same transaction

} // end of updateUsedTrainingTimeUsingEventMaps()

Question: Being that this is my first time doing this, I am unsure of
how exactly this effects (if at all), mass updates that trigger this
method. I learned recently (in SFDev450 class) that Salesforce handles
records in sets of 200 in loops – but I am unsure if that means they also only pass 200 records to the method at once.

Does this mean:

Each 200 records get their own transaction per 200, and by extension, a fresh reset of the Boolean?

OR

Will my 201st record not run the method since it's a second set of
200 being run through the method in the same transaction where the
Boolean is now true?

OR

Will all of my records (let's say 405) be sent to the method at the
same time but just run through the loops in sets of 200 before doing
my final DML update outside of the loop, resulting in all 405 running the method once regardless of how many times subsequent order of executions may start in that transaction?

OR

None of the above? (Please specify)

Many thanks for your insight!

Best Answer

Very astute question! The answer is number 2. You want to put your boolean in your trigger where the class is called from. You'll need a trigger utility class to hold the boolean. This is a large part of why trigger platforms are so useful, particularly ones that have a "trigger main" that acts as a distribution class that follows the logic of a regular base trigger from which your helper classes are called.

Example of Utility class:

Public class TrggrUtility{

   public static boolean RunOnce = False;

}

Test inside of trigger:

If(!TrggrUtility.RunOnce) 
{
   // do... call method
   TrggrUtility.RunOnce = true;

}else{

  // exit trigger or code section

}

Related Solutions

[SalesForce] Apex – how to batch update a ‘ranking’ on all accounts

What you need here is to implement Database.Stateful on your class to retain the index between calls to the execute method, without this the index will reset each time Batch Apex passes the job the next chunk of 200 records (which is the default chunk/scope size via Database.executeBatch).

Using State in Batch Apex

Each execution of a batch Apex job is considered a discrete transaction. For example, a batch Apex job that contains 1,000 records and is executed without the optional scope parameter is considered five transactions of 200 records each.

If you specify Database.Stateful in the class definition, you can maintain state across these transactions. When using Database.Stateful, only instance member variables retain their values between transactions. Static member variables don’t and are reset between transactions. Maintaining state is useful for counting or summarizing records as they're processed. For example, suppose your job processed opportunity records. You could define a method in execute to aggregate totals of the opportunity amounts as they were processed.

If you move your Integer out as a class member this will retain its state between calls, like so.

public class BatchTierUpdate implements Database.Batchable<sObject>
   implements Database.Stateful
{
    public final String Query;
    public Integer rankIndex;

    public BatchTierUpdate()
    {
        Query = 'SELECT Id FROM Account Order by Revenue__c';
        rankIndex = 1;
    }

    public Database.QueryLocator start(Database.BatchableContext BC) 
    {   
        return Database.getQueryLocator(query);
    }

    public void execute(Database.BatchableContext BC, List<Account> scope) 
    {   
        for (Account ac : scope) 
        {
            ac.Rank__c = i;
            rankIndex = rankIndex + 1;
        }
        update scope;
    }

    public void finish(Database.BatchableContext BC) { }    
}

Note: That i have also removed the global and used public, the documentation still shows this, as in the past it was a requirement, these days it is not, unless you want to expose this class to callers outside a managed package.

[SalesForce] How to handle error records in Batch apex

Some things to do:

Have your batch class implement Database.stateful
Declare some variables that are initialized in the constructor to 0. These variables count successes and errors; also a string variable that remembers the records that failed and why (initialized to empty string).
Use Database.update with allOrNothing = false instead of update within execute(). Interrogate each member of Database.SaveResult[] for isSuccess() and count succcesses and failures in your stateful variables from #2. Log in the stateful variable all the errors (id of record, name of record, and error message/exception)
In the finish method, send an email to the sysad of count of successes/failures + string variable of all the failures.
In finish() method, write your batch results to a custom Log__c record(s)

Best Answer

Related Solutions

[SalesForce] Apex – how to batch update a ‘ranking’ on all accounts

[SalesForce] How to handle error records in Batch apex

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