The document provides a comprehensive overview of Batch Apex, a Salesforce feature for processing large datasets efficiently. It covers how Batch Apex works, including the definition of datasets, chunking processes, and post-processing tasks, along with examples of scenarios where it is applicable. Additionally, it explains how to run, schedule, and monitor Batch Apex jobs, as well as testing considerations and best practices.

1. Batch Apex
Dave Helgerson
davehelgerson.com
@davehelgerson

2. Batch Apex Agenda
• High level description of Batch Apex
• How to use Batch Apex
• Simple Code Examples
• Demos in a Salesforce org
• Questions

3. What is Batch Apex?
• Batch Apex is a way to process millions of
records on the Salesforce platform

4. How does Batch Apex work?
• Start by defining a dataset to process through
– Database.QueryLocator
– Custom Iterator
– List Collection

5. How does Batch Apex work? (cont.)
• Then, the dataset is divided into smaller
chunks of records
– Each chunk of dataset processes as a separate
transaction
– Size of each chunk is defined when submitting the
Batch process

6. How does Batch Apex work? (cont.)
• Finally, after all chunks of the dataset have
been processed, post processing can be run
– Send Emails
– Update aggregate totals

7. How does Batch Apex work? (cont.)
• Define the dataset
• Divide and process
• Post processing

8. How does Batch Apex run?
• Asynchronously, of course!
• Like @future methods or Queueable Apex

9. What conditions are ideal for Batch
Apex?
• Tasks that involve large datasets or are
processing intensive
• Source of data is from a single database
object, and Dataset can be retrieved with a
single SOQL statement
• Each unit of work is independent
• Not time-critical

10. Give me scenarios for Batch Apex
processing
• Record Ownership Reassignment
• Data Retention
• Data Cleansing
• Recalculating Apex Managed Sharing
• Other Mass Record Update

11. What does the code look like?
• Class definition implements the
Database.Batchable interface
• Three methods are required
– start()
– execute()
– finally()

12. What does the code look like? (cont.)
• QueryLocator Example

13. What does the code look like? (cont.)
• List Example

14. What does the code look like? (cont.)
• Iterable Example

15. What does the code look like? (cont.)
• Additional Class Attributes
– Database.AllowsCallouts
• 100 callouts per transaction (Winter ’15)
– Database.Stateful
• State is maintained between transactions
• Instance member variables retain their values
• Static member variables are reset
– Scheduable
• Combine the scheduling class with the Batch Apex class
• global void execute(SchedulableContext sc){

16. How do I run a job?
• Batch Apex is invoked programmatically with
Database.executeBatch or
System.scheduleBatch
– Visualforce page controller
– Apex trigger
– Ajax Toolkit
– Execute Anonymous from Force.com IDE or
Developer Console
– Scheduled Job

17. How do I run a job? (cont.)
• Database.executeBatch
– Submits a job to the queue
– Parameters:
• Instance of the class
• Scope (optional)
– Example:
• Database.executeBatch(new ExampleBatch(),
100);

18. How do I run a job? (cont.)
• System.scheduleBatch
– Creates a scheduled job
– Parameters:
• Instance of the class
• Job name
• Time interval, in minutes, after which the job should start
executing
• Scope (optional)
– Example:
• System.scheduleBatch(new ExampleBatch(),
'Test', 5, 100);

19. How do I run a job? (cont.)
• Job is submitted to the queue
– 5 jobs can be processing at once
– 100 jobs can be in the queue at once.
• Flex Queue (Spring ‘15)
• Enable in the “Apex Flex Queue” in Critical Updates
• Job Id is returned
– Track progress by the job Id

20. How do I schedule a job?
• Scheduling from the UI
– Setup -> Develop -> Apex Classes -> Schedule Apex button

21. How do I schedule a job? (cont.)
• Scheduling in Apex
• system.schedule()
• Name
• Cron expression
• Instance of Schedulable class
• Example:
– system.schedule('My Scheduled Job',
'0 15 * * * ?', new ExampleSchedulable());

22. How do I monitor a job?
• Setup -> Monitor -> Jobs -> Apex Jobs
• Shows active and completed job information

23. How do I monitor a job? (cont.)
• AsyncApexJob
– Accessible in Apex

24. How do I test Batch Apex?
• Use Test.startTest() and Test.endTest()
• Asynchronous processes run synchronously
when the Test.endTest() command executes
• The execute() method may only be invoked
once

25. How do I test Batch Apex?

26. Considerations Summary
• QueryLocator - maximum of 50m records
• Custom Iterators - maximum of 50k records
• Governor limits apply to each invocation of
the execute method()
• @future methods cannot be called
• Timing is determined by Salesforce
• 5 concurrent jobs can process at once
• 100 jobs can be in the queue

27. Demo
• Submitting
• Scheduling
• Monitoring

28. Questions?
davehelgerson.com
@davehelgerson