How To Run Batch Class From Anonymous Window In Salesforce
Batch Apex Instance In Salesforce
Batch Apex Instance In Salesforce
What is Batch Apex in Salesforce?
Batch form in salesforce is used to run large jobs (think thousands or millions of records!) that would exceed normal processing limits. Using Batch Noon, you tin can procedure records asynchronously in batches (hence the name, "Batch Apex") to stay within platform limits. If you have a lot of records to procedure, for example, data cleansing or archiving, Batch Noon is probably your best solution.
Here's how Batch Apex works nether the hood. Let'southward say you want to process 1 million records using Batch Noon. The execution logic of the batch class is called once for each batch of records you are processing. Each time you invoke a batch class, the job is placed on the Noon task queue and is executed every bit a discrete transaction.
Reward of using batch Apex
- Every transaction starts with a new set of governor limits, making information technology easier to ensure that your code stays within the governor execution limits.
- If one batch fails to procedure successfully, all other successful batch transactions aren't rolled back
Batch Apex Syntax
To write a Batch Apex class, your class must implement theDatabase.Batchable interface and include the post-obit three methods:
- start
- Commencement method is automatically called at the beginning of the apex task. This method will collect record or objects on which the performance should be performed. These records are divided into subtasks and pass those to execute method.
Used to collect the records or objects to be passed to the interface methodexecute for processing. This method is called once at the offset of a Batch Apex task and returns either a Database.QueryLocator object or an Iterable that contains the records or objects passed to the chore.
Almost of the time aQueryLocator does the trick with a elementary SOQL query to generate the scope of objects in the batch chore. But if you need to practise something crazy like loop through the results of an API call or pre-procedure records earlier being passed to theexecute method, you lot might desire to check out the Custom Iterators link in the Resource section.
With the QueryLocator object, the governor limit for the full number of records retrieved past SOQL queries is bypassed and you can query upwardly to 50 million records. However, with an Iterable, the governor limit for the full number of records retrieved past SOQL queries is still enforced.
- execute
- Execute Method performs an operation which we desire to perform on the records fetched from outset method.
Performs the actual processing for each chunk or "batch" of data passed to the method. The default batch size is 200 records. Batches of records are not guaranteed to execute in the order they are received from thekickoff method.
This method takes the post-obit:
- A reference to theDatabase.BatchableContext object.
- A list of sObjects, such asList<sObject>, or a list of parameterized types. If yous are using aDatabase.QueryLocator, use the returned list.
- finish
Finish method executes afterward all batches are processed. Use this method to send confirmation email notifications
- Used to execute post-processing operations (for instance, sending an email) and is called once afterwards all batches are candy.
Hither's what the skeleton of a Batch Noon class looks like:
global class MyBatchClass implements Database.Batchable<sObject> { global (Database.QueryLocator | Iterable<sObject>) outset(Database.BatchableContext bc) { // collect the batches of records or objects to exist passed to execute } global void execute(Database.BatchableContext bc, List<P> records){ // process each batch of records } global void cease(Database.BatchableContext bc){ // execute whatsoever mail service-processing operations } } Primal points about batch Apex
- To use batch Noon, write an Noon class that implements Database.Batchable interface and brand your course global
- Implement the following 3 methods
-
- start()
- execute()
- finish()
-
- The default batch size is 200
Monitoring Batch Noon
To monitor or terminate the execution of the batch Apex job, from Setup, enter Noon Jobs in the Quick Detect box, and then select Apex Jobs.
Batch form in salesforce
Here is example of Batch class in salesforce
global grade BatchApexExample implements Database.Batchable<sObject> { global Database.QueryLocator start(Database.BatchableContext BC) { // collect the batches of records or objects to be passed to execute String query = 'SELECT Id, Name FROM Business relationship'; return Database.getQueryLocator(query); } global void execute(Database.BatchableContext BC, List<Account> accList) { // process each batch of records default size is 200 for(Account acc : accList) { // Update the Account Name acc.Name = acc.Name + 'sfdcpoint'; } try { // Update the Business relationship Record update accList; } catch(Exception e) { System.debug(e); } } global void cease(Database.BatchableContext BC) { // execute any post-processing operations like sending email } } Invoking a Batch Class
To invoke a batch class, simply instantiate it and and so call Database.executeBatch with the instance:
MyBatchClass myBatchObject = new MyBatchClass(); Id batchId = Database.executeBatch(myBatchObject);
You can also optionally pass a second telescopic parameter to specify the number of records that should be passed into the execute method for each batch. Pro tip: y'all might want to limit this batch size if you are running into governor limits.
Id batchId = Database.executeBatch(myBatchObject, 100);
Each batch Apex invocation creates an AsyncApexJob record so that yous can track the job's progress. You can view the progress via SOQL or manage your task in the Apex Task Queue. Nosotros'll talk nigh the Task Queue shortly.
AsyncApexJob job = [SELECT Id, Condition, JobItemsProcessed, TotalJobItems, NumberOfErrors FROM AsyncApexJob WHERE ID = :batchId ];
Scheduling Batch Apex
tin also apply theSchedulable interface with batch Noon classes. The following example implements theSchedulable interface for a batch Apex class calledbatchable:
global class scheduledBatchable implements Schedulable { global void execute(SchedulableContext sc) { BatchApexExample b = new BatchApexExample(); Database.executeBatch(b); } } Test class for batch Apex
@isTest individual class BatchApexExampleTest { static testmethod void test() { // Create test accounts to be updated past batch Account[] accList = new Listing(); for (Integer i=0;i<400;i++) { Business relationship ac = new Account(Name = 'Account ' + i); accList.add together(ac); } insert accList; Examination.startTest(); BatchApexExample b = new BatchApexExample(); Database.executeBatch(b); Exam.stopTest(); // Verify accounts updated Account[] accUpdatedList = [SELECT Id, Name FROM Business relationship]; System.assert(accUpdatedList[0].Name.Contains('sfdcpoint')); } } Best Practices for batch Noon
As with future methods, in that location are a few things you lot desire to continue in mind when using Batch Apex. To ensure fast execution of batch jobs, minimize Spider web service callout times and tune queries used in your batch Apex lawmaking. The longer the batch job executes, the more likely other queued jobs are delayed when many jobs are in the queue. Best practices include:
- Only use Batch Apex if you have more than i batch of records. If you lot don't have enough records to run more than one batch, y'all are probably improve off using Queueable Noon.
- Tune any SOQL query to gather the records to execute every bit quickly as possible.
- Minimize the number of asynchronous requests created to minimize the hazard of delays.
- Use extreme intendance if yous are planning to invoke a batch chore from a trigger. You must be able to guarantee that the trigger won't add more than batch jobs than the limit.
For more details about batch noon refer to batch apex trailhead
Source: https://www.sfdcpoint.com/salesforce/batch-apex-example-in-salesforce/
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