When is a batch class instantiated when you schedule it?












1















QUESTION: when you instantiate a class in a scheduled apex job, is the class instantiated at the time of the schedule, or at the scheduled time of execution?



Here's my situation...
I have a custom object called Blast, which schedules a bulk SMS send. That object record includes a DateTime field that designates when the blast will happen; for this example, let's say the blast happens next Tuesday at 1:00 pm.



The blast has some unknown number of recipients -- very possibly 20-50k, which are stored as CampaignMembers. So, at the designated time, I have a batch apex class that retrieves all of the recipient info from the CampaignMember records and makes the api call.



When a user creates/updates the Blast record today and sets status to "queued", I'm creating a scheduled apex job, instantiating my batch apex class and providing the blast record, from which it pulls necessary data.



I want to build into the batch apex class a check that verifies the blast record still exists before executing the blast. But I'm not clear on whether that class is instantiated today (when the job is scheduled), or next Tuesday at 1:00pm when it has been scheduled to run.










share|improve this question



























    1















    QUESTION: when you instantiate a class in a scheduled apex job, is the class instantiated at the time of the schedule, or at the scheduled time of execution?



    Here's my situation...
    I have a custom object called Blast, which schedules a bulk SMS send. That object record includes a DateTime field that designates when the blast will happen; for this example, let's say the blast happens next Tuesday at 1:00 pm.



    The blast has some unknown number of recipients -- very possibly 20-50k, which are stored as CampaignMembers. So, at the designated time, I have a batch apex class that retrieves all of the recipient info from the CampaignMember records and makes the api call.



    When a user creates/updates the Blast record today and sets status to "queued", I'm creating a scheduled apex job, instantiating my batch apex class and providing the blast record, from which it pulls necessary data.



    I want to build into the batch apex class a check that verifies the blast record still exists before executing the blast. But I'm not clear on whether that class is instantiated today (when the job is scheduled), or next Tuesday at 1:00pm when it has been scheduled to run.










    share|improve this question

























      1












      1








      1








      QUESTION: when you instantiate a class in a scheduled apex job, is the class instantiated at the time of the schedule, or at the scheduled time of execution?



      Here's my situation...
      I have a custom object called Blast, which schedules a bulk SMS send. That object record includes a DateTime field that designates when the blast will happen; for this example, let's say the blast happens next Tuesday at 1:00 pm.



      The blast has some unknown number of recipients -- very possibly 20-50k, which are stored as CampaignMembers. So, at the designated time, I have a batch apex class that retrieves all of the recipient info from the CampaignMember records and makes the api call.



      When a user creates/updates the Blast record today and sets status to "queued", I'm creating a scheduled apex job, instantiating my batch apex class and providing the blast record, from which it pulls necessary data.



      I want to build into the batch apex class a check that verifies the blast record still exists before executing the blast. But I'm not clear on whether that class is instantiated today (when the job is scheduled), or next Tuesday at 1:00pm when it has been scheduled to run.










      share|improve this question














      QUESTION: when you instantiate a class in a scheduled apex job, is the class instantiated at the time of the schedule, or at the scheduled time of execution?



      Here's my situation...
      I have a custom object called Blast, which schedules a bulk SMS send. That object record includes a DateTime field that designates when the blast will happen; for this example, let's say the blast happens next Tuesday at 1:00 pm.



      The blast has some unknown number of recipients -- very possibly 20-50k, which are stored as CampaignMembers. So, at the designated time, I have a batch apex class that retrieves all of the recipient info from the CampaignMember records and makes the api call.



      When a user creates/updates the Blast record today and sets status to "queued", I'm creating a scheduled apex job, instantiating my batch apex class and providing the blast record, from which it pulls necessary data.



      I want to build into the batch apex class a check that verifies the blast record still exists before executing the blast. But I'm not clear on whether that class is instantiated today (when the job is scheduled), or next Tuesday at 1:00pm when it has been scheduled to run.







      schedulebatch






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      asked yesterday









      PatMcClellan__cPatMcClellan__c

      791220




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          It's instantiated when new SomeBatchJobName() is called, then serialized when System.scheduleBatch(...) is called. So the data stored in the object will be from the moment of instantiation (now), not when it is eventually pulled from the queue and executed. This is also true for scheduled and queueable jobs, too.






          share|improve this answer
























          • OK, thanks. That's what I thought would happen, just wanted to confirm. So that means any changes (between now and next Tuesday) to the data I use to instantiate the object will not be reflected. So... I'm thinking I need another class, that executes next Tuesday and instantiates the batch object then.

            – PatMcClellan__c
            yesterday











          • @PatMcClellan__c Without seeing your code, hard to say, but remember you can also do other stuff in your start method besides just providing a query locator. During the start method might be a perfect time to do any other calculations or queries you need to perform to see if you want to continue or not. You can also use System.abortJob in the start method if you want to cancel your job early (the job Id comes from the BatchableContext object).

            – sfdcfox
            yesterday











          • Ah... I was wondering about that. So, instead of providing the entire blast record when I instantiate, I just provide the recordId. Then, in the start method, I do a soql search on it, pull the data at that point in time, or abort if the record no longer exists.

            – PatMcClellan__c
            yesterday











          • @PatMcClellan__c Yes, you should always query for the data you're going to work on as late as possible, especially when using asynchronous code that might not be called for a long time.

            – sfdcfox
            yesterday











          • I can't find docs on how to pull the jobId while inside the start method. Would it be something like... BC.getJobId() ?

            – PatMcClellan__c
            yesterday





















          0














          For the benefit of clarity, I'll share my revised code... the object is actually called Wave, not Blast.



          global class QueueWave implements Database.Batchable<SObject>, Database.Stateful {
          global String waveId;
          global String body;
          global String messageServiceLabel;
          global Integer recipientCount;
          global String emailAddress;
          global String waveName;
          global String userId;

          global QueueWave(String waveId) {
          this.waveId = waveId;
          }


          The constructor does nothing except store the recordId at the time this batch class is scheduled. I'm using try-catch, catching QueryException which aborts the job.



          global Database.QueryLocator start(Database.BatchableContext BC){
          String query;
          if(Wave__c.SObjectType.getDescribe().isAccessible()){
          try{
          Wave__c wave = [
          SELECT [fields I need, which may have been updated since batch was scheduled]
          FROM Wave__c
          WHERE Id = :this.waveId
          LIMIT 1];

          //set global vars with data from the wave record
          . . .

          query = // build my query string here

          }catch(QueryException qe){
          System.debug('QueryException on ' + BC.getJobId() + ' ' + qe);
          System.abortJob(BC.getJobId());
          }
          }

          return Database.getQueryLocator(query);
          }





          share|improve this answer

























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            2 Answers
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            3














            It's instantiated when new SomeBatchJobName() is called, then serialized when System.scheduleBatch(...) is called. So the data stored in the object will be from the moment of instantiation (now), not when it is eventually pulled from the queue and executed. This is also true for scheduled and queueable jobs, too.






            share|improve this answer
























            • OK, thanks. That's what I thought would happen, just wanted to confirm. So that means any changes (between now and next Tuesday) to the data I use to instantiate the object will not be reflected. So... I'm thinking I need another class, that executes next Tuesday and instantiates the batch object then.

              – PatMcClellan__c
              yesterday











            • @PatMcClellan__c Without seeing your code, hard to say, but remember you can also do other stuff in your start method besides just providing a query locator. During the start method might be a perfect time to do any other calculations or queries you need to perform to see if you want to continue or not. You can also use System.abortJob in the start method if you want to cancel your job early (the job Id comes from the BatchableContext object).

              – sfdcfox
              yesterday











            • Ah... I was wondering about that. So, instead of providing the entire blast record when I instantiate, I just provide the recordId. Then, in the start method, I do a soql search on it, pull the data at that point in time, or abort if the record no longer exists.

              – PatMcClellan__c
              yesterday











            • @PatMcClellan__c Yes, you should always query for the data you're going to work on as late as possible, especially when using asynchronous code that might not be called for a long time.

              – sfdcfox
              yesterday











            • I can't find docs on how to pull the jobId while inside the start method. Would it be something like... BC.getJobId() ?

              – PatMcClellan__c
              yesterday


















            3














            It's instantiated when new SomeBatchJobName() is called, then serialized when System.scheduleBatch(...) is called. So the data stored in the object will be from the moment of instantiation (now), not when it is eventually pulled from the queue and executed. This is also true for scheduled and queueable jobs, too.






            share|improve this answer
























            • OK, thanks. That's what I thought would happen, just wanted to confirm. So that means any changes (between now and next Tuesday) to the data I use to instantiate the object will not be reflected. So... I'm thinking I need another class, that executes next Tuesday and instantiates the batch object then.

              – PatMcClellan__c
              yesterday











            • @PatMcClellan__c Without seeing your code, hard to say, but remember you can also do other stuff in your start method besides just providing a query locator. During the start method might be a perfect time to do any other calculations or queries you need to perform to see if you want to continue or not. You can also use System.abortJob in the start method if you want to cancel your job early (the job Id comes from the BatchableContext object).

              – sfdcfox
              yesterday











            • Ah... I was wondering about that. So, instead of providing the entire blast record when I instantiate, I just provide the recordId. Then, in the start method, I do a soql search on it, pull the data at that point in time, or abort if the record no longer exists.

              – PatMcClellan__c
              yesterday











            • @PatMcClellan__c Yes, you should always query for the data you're going to work on as late as possible, especially when using asynchronous code that might not be called for a long time.

              – sfdcfox
              yesterday











            • I can't find docs on how to pull the jobId while inside the start method. Would it be something like... BC.getJobId() ?

              – PatMcClellan__c
              yesterday
















            3












            3








            3







            It's instantiated when new SomeBatchJobName() is called, then serialized when System.scheduleBatch(...) is called. So the data stored in the object will be from the moment of instantiation (now), not when it is eventually pulled from the queue and executed. This is also true for scheduled and queueable jobs, too.






            share|improve this answer













            It's instantiated when new SomeBatchJobName() is called, then serialized when System.scheduleBatch(...) is called. So the data stored in the object will be from the moment of instantiation (now), not when it is eventually pulled from the queue and executed. This is also true for scheduled and queueable jobs, too.







            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered yesterday









            sfdcfoxsfdcfox

            259k12204447




            259k12204447













            • OK, thanks. That's what I thought would happen, just wanted to confirm. So that means any changes (between now and next Tuesday) to the data I use to instantiate the object will not be reflected. So... I'm thinking I need another class, that executes next Tuesday and instantiates the batch object then.

              – PatMcClellan__c
              yesterday











            • @PatMcClellan__c Without seeing your code, hard to say, but remember you can also do other stuff in your start method besides just providing a query locator. During the start method might be a perfect time to do any other calculations or queries you need to perform to see if you want to continue or not. You can also use System.abortJob in the start method if you want to cancel your job early (the job Id comes from the BatchableContext object).

              – sfdcfox
              yesterday











            • Ah... I was wondering about that. So, instead of providing the entire blast record when I instantiate, I just provide the recordId. Then, in the start method, I do a soql search on it, pull the data at that point in time, or abort if the record no longer exists.

              – PatMcClellan__c
              yesterday











            • @PatMcClellan__c Yes, you should always query for the data you're going to work on as late as possible, especially when using asynchronous code that might not be called for a long time.

              – sfdcfox
              yesterday











            • I can't find docs on how to pull the jobId while inside the start method. Would it be something like... BC.getJobId() ?

              – PatMcClellan__c
              yesterday





















            • OK, thanks. That's what I thought would happen, just wanted to confirm. So that means any changes (between now and next Tuesday) to the data I use to instantiate the object will not be reflected. So... I'm thinking I need another class, that executes next Tuesday and instantiates the batch object then.

              – PatMcClellan__c
              yesterday











            • @PatMcClellan__c Without seeing your code, hard to say, but remember you can also do other stuff in your start method besides just providing a query locator. During the start method might be a perfect time to do any other calculations or queries you need to perform to see if you want to continue or not. You can also use System.abortJob in the start method if you want to cancel your job early (the job Id comes from the BatchableContext object).

              – sfdcfox
              yesterday











            • Ah... I was wondering about that. So, instead of providing the entire blast record when I instantiate, I just provide the recordId. Then, in the start method, I do a soql search on it, pull the data at that point in time, or abort if the record no longer exists.

              – PatMcClellan__c
              yesterday











            • @PatMcClellan__c Yes, you should always query for the data you're going to work on as late as possible, especially when using asynchronous code that might not be called for a long time.

              – sfdcfox
              yesterday











            • I can't find docs on how to pull the jobId while inside the start method. Would it be something like... BC.getJobId() ?

              – PatMcClellan__c
              yesterday



















            OK, thanks. That's what I thought would happen, just wanted to confirm. So that means any changes (between now and next Tuesday) to the data I use to instantiate the object will not be reflected. So... I'm thinking I need another class, that executes next Tuesday and instantiates the batch object then.

            – PatMcClellan__c
            yesterday





            OK, thanks. That's what I thought would happen, just wanted to confirm. So that means any changes (between now and next Tuesday) to the data I use to instantiate the object will not be reflected. So... I'm thinking I need another class, that executes next Tuesday and instantiates the batch object then.

            – PatMcClellan__c
            yesterday













            @PatMcClellan__c Without seeing your code, hard to say, but remember you can also do other stuff in your start method besides just providing a query locator. During the start method might be a perfect time to do any other calculations or queries you need to perform to see if you want to continue or not. You can also use System.abortJob in the start method if you want to cancel your job early (the job Id comes from the BatchableContext object).

            – sfdcfox
            yesterday





            @PatMcClellan__c Without seeing your code, hard to say, but remember you can also do other stuff in your start method besides just providing a query locator. During the start method might be a perfect time to do any other calculations or queries you need to perform to see if you want to continue or not. You can also use System.abortJob in the start method if you want to cancel your job early (the job Id comes from the BatchableContext object).

            – sfdcfox
            yesterday













            Ah... I was wondering about that. So, instead of providing the entire blast record when I instantiate, I just provide the recordId. Then, in the start method, I do a soql search on it, pull the data at that point in time, or abort if the record no longer exists.

            – PatMcClellan__c
            yesterday





            Ah... I was wondering about that. So, instead of providing the entire blast record when I instantiate, I just provide the recordId. Then, in the start method, I do a soql search on it, pull the data at that point in time, or abort if the record no longer exists.

            – PatMcClellan__c
            yesterday













            @PatMcClellan__c Yes, you should always query for the data you're going to work on as late as possible, especially when using asynchronous code that might not be called for a long time.

            – sfdcfox
            yesterday





            @PatMcClellan__c Yes, you should always query for the data you're going to work on as late as possible, especially when using asynchronous code that might not be called for a long time.

            – sfdcfox
            yesterday













            I can't find docs on how to pull the jobId while inside the start method. Would it be something like... BC.getJobId() ?

            – PatMcClellan__c
            yesterday







            I can't find docs on how to pull the jobId while inside the start method. Would it be something like... BC.getJobId() ?

            – PatMcClellan__c
            yesterday















            0














            For the benefit of clarity, I'll share my revised code... the object is actually called Wave, not Blast.



            global class QueueWave implements Database.Batchable<SObject>, Database.Stateful {
            global String waveId;
            global String body;
            global String messageServiceLabel;
            global Integer recipientCount;
            global String emailAddress;
            global String waveName;
            global String userId;

            global QueueWave(String waveId) {
            this.waveId = waveId;
            }


            The constructor does nothing except store the recordId at the time this batch class is scheduled. I'm using try-catch, catching QueryException which aborts the job.



            global Database.QueryLocator start(Database.BatchableContext BC){
            String query;
            if(Wave__c.SObjectType.getDescribe().isAccessible()){
            try{
            Wave__c wave = [
            SELECT [fields I need, which may have been updated since batch was scheduled]
            FROM Wave__c
            WHERE Id = :this.waveId
            LIMIT 1];

            //set global vars with data from the wave record
            . . .

            query = // build my query string here

            }catch(QueryException qe){
            System.debug('QueryException on ' + BC.getJobId() + ' ' + qe);
            System.abortJob(BC.getJobId());
            }
            }

            return Database.getQueryLocator(query);
            }





            share|improve this answer






























              0














              For the benefit of clarity, I'll share my revised code... the object is actually called Wave, not Blast.



              global class QueueWave implements Database.Batchable<SObject>, Database.Stateful {
              global String waveId;
              global String body;
              global String messageServiceLabel;
              global Integer recipientCount;
              global String emailAddress;
              global String waveName;
              global String userId;

              global QueueWave(String waveId) {
              this.waveId = waveId;
              }


              The constructor does nothing except store the recordId at the time this batch class is scheduled. I'm using try-catch, catching QueryException which aborts the job.



              global Database.QueryLocator start(Database.BatchableContext BC){
              String query;
              if(Wave__c.SObjectType.getDescribe().isAccessible()){
              try{
              Wave__c wave = [
              SELECT [fields I need, which may have been updated since batch was scheduled]
              FROM Wave__c
              WHERE Id = :this.waveId
              LIMIT 1];

              //set global vars with data from the wave record
              . . .

              query = // build my query string here

              }catch(QueryException qe){
              System.debug('QueryException on ' + BC.getJobId() + ' ' + qe);
              System.abortJob(BC.getJobId());
              }
              }

              return Database.getQueryLocator(query);
              }





              share|improve this answer




























                0












                0








                0







                For the benefit of clarity, I'll share my revised code... the object is actually called Wave, not Blast.



                global class QueueWave implements Database.Batchable<SObject>, Database.Stateful {
                global String waveId;
                global String body;
                global String messageServiceLabel;
                global Integer recipientCount;
                global String emailAddress;
                global String waveName;
                global String userId;

                global QueueWave(String waveId) {
                this.waveId = waveId;
                }


                The constructor does nothing except store the recordId at the time this batch class is scheduled. I'm using try-catch, catching QueryException which aborts the job.



                global Database.QueryLocator start(Database.BatchableContext BC){
                String query;
                if(Wave__c.SObjectType.getDescribe().isAccessible()){
                try{
                Wave__c wave = [
                SELECT [fields I need, which may have been updated since batch was scheduled]
                FROM Wave__c
                WHERE Id = :this.waveId
                LIMIT 1];

                //set global vars with data from the wave record
                . . .

                query = // build my query string here

                }catch(QueryException qe){
                System.debug('QueryException on ' + BC.getJobId() + ' ' + qe);
                System.abortJob(BC.getJobId());
                }
                }

                return Database.getQueryLocator(query);
                }





                share|improve this answer















                For the benefit of clarity, I'll share my revised code... the object is actually called Wave, not Blast.



                global class QueueWave implements Database.Batchable<SObject>, Database.Stateful {
                global String waveId;
                global String body;
                global String messageServiceLabel;
                global Integer recipientCount;
                global String emailAddress;
                global String waveName;
                global String userId;

                global QueueWave(String waveId) {
                this.waveId = waveId;
                }


                The constructor does nothing except store the recordId at the time this batch class is scheduled. I'm using try-catch, catching QueryException which aborts the job.



                global Database.QueryLocator start(Database.BatchableContext BC){
                String query;
                if(Wave__c.SObjectType.getDescribe().isAccessible()){
                try{
                Wave__c wave = [
                SELECT [fields I need, which may have been updated since batch was scheduled]
                FROM Wave__c
                WHERE Id = :this.waveId
                LIMIT 1];

                //set global vars with data from the wave record
                . . .

                query = // build my query string here

                }catch(QueryException qe){
                System.debug('QueryException on ' + BC.getJobId() + ' ' + qe);
                System.abortJob(BC.getJobId());
                }
                }

                return Database.getQueryLocator(query);
                }






                share|improve this answer














                share|improve this answer



                share|improve this answer








                edited 9 hours ago

























                answered yesterday









                PatMcClellan__cPatMcClellan__c

                791220




                791220






























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