Asynchronous apex

Salesforce Asynchronous Batch Process

1. Asynchronous Apex Begin Your Salesforce Coding Adventure Created By: furuCRM Japan Created Date: 2021/1/11

2. Agenda What is Async Proccessing ? Understanding 4 type Async Sample code Q&A

3. What is Async Proccessing ? Explain the difference between synchronous and asynchronous processing The key benefits of asynchronous processing include: User efficiency Scalability Higher Limits

4. What is Async Proccessing ? Choose which kind of asynchronous Apex to use in various scenarios

5. Future Methods Future methods are typically used for: Async processing (simple and often) Long-running operations (Callouts to external web services) Separating mixed DML operations How can I define future method? with the future annotation must be static methods, and can only return a void type Specify (callout=true) to allow callouts

6. Future Methods You can invoke future methods the same way you invoke any other method. However, a future method can’t invoke another future method. Methods with the future annotation have the following limits: Total number of SOQL queries issued: 200, Total heap size: 12MB, Maximum CPU time on the Salesforce servers:60,000 milliseconds Maximum number of methods with the future annotation allowed per Apex invocation: Synchronous Limit: 50, Asynchronous Limit: 0 in batch and future contexts; 1 in queueable context The maximum number of future method invocations per a 24-hour period is 250,000 or the number of user licenses in your organization multiplied by 200, whichever is greater. This limit is for your entire org and is shared with all asynchronous Apex: Batch Apex, Queueable Apex, scheduled Apex, and future methods. To check how many asynchronous Apex executions are available, make a request to REST API limits resource: Reference: https://developer.salesforce.com/docs/atlas.en-us.224.0.api_rest.meta/api_rest/dome_limits.htm

7. Future Methods Advantages : Asynchronous processing without a concurrent limit (queue) Easier and quicker to implement as opposed to Batch Disadvantages Parameters passed in can be only of Primitive type Can’t chain @future methods Difficult access to job ID

8. Queueable Apex Queueable Apex are typically used for: Chaining jobs: You can chain one job to another job by starting a second job from a running job. Chaining jobs is useful if your process depends on another process to have run first You need @future method with support for non-primitive type. Your queueable class can contain member variables of non-primitive data types, such as sObjects or custom Apex types. Those objects can be accessed when the job executes Asynchronous monitoring How can I define Queueable Apex ? Implement the Queueable interface Define execute() method How can I enqueue a job ? ID jobID = System. enqueueJob ( SomeClass );

9. Queueable Apex Example The job is added to the queue and will be processed when system resources become available. You can monitor the status of your job programmatically by querying AsyncApexJob or through the user interface in Setup by entering Apex Jobs in the Quick Find box, then selecting Apex Jobs. Queueable Apex have the following limits: Total number of SOQL queries issued: 200, Total heap size: 12MB, Maximum CPU time on the Salesforce servers:60,000 milliseconds The maximum number of asynchronous Apex method executions per a 24-hour period is 250,000 or the number of user licenses in your organization multiplied by 200, whichever is greater. You can add up to 50 jobs to the queue with System.enqueueJob in a single transaction(Synchronous Limit). In asynchronous transactions (for example, from a batch Apex job), you can add only one job to the queue with System.enqueueJob

10. Queueable Apex: chaining jobs When? To run a job after some other processing is done first by another job How? submit the second job from the execute() method of your queueable class You can add only one job from an executing job No limit is enforced on the depth of chained jobs. But For Developer Edition and Trial organizations: 5 jobs including the initial parent queueable job

11. Batch Apex When should I use it? Complex long running processes (thousands of records). For example: Data cleansing or archiving of records. Batch Apex operates over small batches of records, covering your entire record set and breaking the processing down to manageable chunks Asynchronous processing Scheduled jobs

12. Batch Apex: How to define a Batch? I mplement Database.Batchable  Interface T hree methods that must be implemented: start() Database.QueryLocator : 50M records, using a simple query (SELECT) to generate the scope of objects in the batch job Iterable : 50, 000 records, to create a complex scope for the batch job execute() To do the required processing for each chunk or batch of data passed to the method Default batch size: 200 record Batches of records are not guaranteed to execute in the order they are received from the start method. finish() Is called after all batches are processed To send confirmation emails or execute post-processing operations Chaining Batch Jobs: Starting with API version 26.0. By calling Database.executeBatch or System.scheduleBatch . The new batch job will start after the current batch job finishes. Each execution of a batch Apex job is considered a discrete transaction The Apex governor limits are reset for each transaction If the first transaction succeeds but the second fails, the database updates made in the first transaction are not rolled back. To invoke a batch class, simply instantiate it and then call Database.executeBatch with the instance: To specify the number of records that should be passed into the execute method for each batch.

13. Batch Apex: Using State 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. Static member variables don’t retain their values and are reset back to original value between transactions 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. Maintaining state is useful for counting or summarizing records as they’re processed. 

14. Batch Apex: Sample Code

15. Batch Apex: Governor Limits Up to 5 batch jobs can be queued or active concurrently. Up to 100 Holding batch jobs can be held in the Apex flex queue. In a running test, you can submit a maximum of 5 batch jobs. The maximum number of batch Apex method executions per 24-hour period is 250,000, or the number of user licenses in your org multiplied by 200—whichever is greater. Method executions include executions of the start, execute, and finish methods. A maximum of 50 million records can be returned in the Database.QueryLocator object. If the start method of the batch class returns a QueryLocator , the optional scope parameter of Database.executeBatch can have a maximum value of 2,000. If set to a higher value, Salesforce chunks the records returned by the QueryLocator into smaller batches of up to 2,000 records. If the start method of the batch class returns an iterable , the scope parameter value has no upper limit. However, if you use a high number, you can run into other limits. The start, execute, and finish methods can implement up to 100 callouts each. Only one batch Apex job's start method can run at a time in an org. Batch jobs that haven’t started yet remain in the queue until they're started. Note that this limit doesn’t cause any batch job to fail and execute methods of batch Apex jobs still run in parallel if more than one job is running.

16. Apex Scheduler When should I use it? Delay execution, run Apex classes at a specified time Daily or weekly maintenance tasks using Batch Apex

17. Scheduled Apex Syntax implement the Schedulable interface for the class Execute() method must be implemented Use the System.Schedule method to execute three arguments: a name for the job, an expression used to represent the time and date the job is scheduled to run, and the name of the class. Using the  System.scheduleBatch  Method for Batch Jobs doesn’t require the implementation of the  Schedulable  interface This method is available only for batch classes

18. Scheduled Apex Syntax

19. Scheduled Apex : Governor Limits Maximum 100 jobs can be scheduled concurrently The maximum number of scheduled Apex executions per a 24-hour period is 250,000 or the number of user licenses in your organization multiplied by 200, whichever is greater. This limit is for your entire org and is shared with all asynchronous Apex: Batch Apex, Queueable Apex, scheduled Apex, and future methods. Synchronous Web service callouts are not supported from scheduled Apex. To be able to make callouts, make an asynchronous callout by placing the callout in a method annotated with @future(callout=true) and call this method from scheduled Apex. However, if your scheduled Apex executes a batch job, callouts are supported from the batch class

20. Scheduled Apex : Sample Code

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