Batch Apex vs. Queueable Apex:
Which One to Use?
In Salesforce development, efficiency and scalability are crucial when dealing with large datasets and complex processes. Asynchronous Apex is a key feature that enables developers to run operations in the background, freeing up system resources for more immediate tasks. Batch Apex and Queueable Apex are two of the most used asynchronous Apex features. While both handle tasks that need to run in the background, they serve different purposes. Understanding which one to use can significantly improve the performance of your application. This blog will explore these features and their respective advantages and limitations.
What is Batch Apex?
Batch Apex is a powerful Salesforce feature that can process large amounts of data by dividing them into smaller, more manageable chunks or batches.
Batch Apex is a global class that implements the Database.Batchable interface and must be explicitly implemented by the developer.
With Batch Apex, we ensure that records can be processed without exceeding governor limits, which could otherwise impact system performance.
The advantages Batch Apex offers:
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Every transaction starts with a new set of governor limits, ensuring your code stays within these limits easier.
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If one batch fails to process successfully, all other successful batch transactions aren’t rolled back.
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Batch Apex allows you to split your tasks into smaller chunks of up to 2000 records.
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Batch Apex will only process new batches if the current batch is completed.
These are the limitations when working with Batch Apex:
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You can only have five queued or active batch jobs at one time.
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Up to 50 million records can be returned to the Database.QueryLocator object. If more than 50 million records are returned, the batch job is immediately terminated and marked as Failed.
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Methods with @future annotation cannot be called from Batch Apex.
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The start, execute, and finish methods can implement up to 100 callouts.
What is Queueable Apex?
Queueable Apex is another form of asynchronous Apex that provides more control than future methods but is lighter and faster than Batch Apex.
Time-consuming Apex processes can be run asynchronously by implementing the Queueable interface and adding a job to the Apex job queue.
This allows developers to queue up jobs that run in the background. Each queued job runs when system resources become available.
The advantages Queueable Apex offers:
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Queueable Apex has higher governor limits than synchronous Apex, which allows it to handle more complex processes and work with large amounts of data.
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Queueable class can contain variables of non-primitive data types, such as sObject or custom Apex types, which is impossible with @future annotated methods.
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Submitting a job with the System.enqueueJob method returns the new Job's ID. This allows you to monitor its status and progress at any given time.
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Queueable Apex allows you to chain jobs, meaning that one Queueable job can enqueue another Queueable job as part of its execution. This is useful when subsequent processing is required.
These are the limitations when working with Queueable Apex:
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Execution of a queued job counts one time against the shared limit for asynchronous Apex method executions.
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In a single transaction, you can add a maximum of 50 jobs in the queue.
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While chaining jobs, only one child job can exist for each parent job.
Batch Apex vs. Queueable Apex: Key Differences
Although both Batch Apex and Queueable Apex are used for asynchronous processing, they have the following key differences:
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Batch Apex is suited for processing a large dataset and dividing it into smaller batches, whereas Queueable Apex is more suited for handling individual asynchronous jobs that are too complex for a single transaction.
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Batch Apex involves more coding setup such as start, execute and finish methods. On the other hand, Queueable Apex requires less code and is simpler to implement.
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Batch Apex supports job chaining, although it is less common and more complex. On the other hand, Queueable Apex is more suited for sequential operations.
Conclusion
Choosing between Batchable Apex and Queueable Apex comes down to the nature and requirements of your task.
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Use Batch Apex when working with large amounts of data or complex operations that need to be processed on smaller chunks. It is commonly used for mass data updates and data cleansing.
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Use Queueable Apex when working with background jobs that need to be chained together.
By selecting the right tool for the job, you can ensure your Salesforce application runs smoothly and efficiently, balancing the need for performance and resource management.