Preventing row locks in Salesforce Apex, especially during batch processing, is crucial for maintaining the efficiency and reliability of your applications. Here are some strategies and best practices to consider:
- Use the ‘FOR UPDATE’ SOQL Query: When you execute a SOQL query with the ‘FOR UPDATE’ keyword, Salesforce locks the records that are returned by the query. This ensures that other processes or batches cannot modify these records simultaneously. For example, you can write a query like
List<Account> accounts = [SELECT Id, Name FROM ACCOUNT LIMIT 10 FOR UPDATE];
to lock the accounts being processed. - Optimize Batch Size and Processing Mode: If you’re using Bulk API for processing records, consider reducing the batch size. Smaller batches mean fewer records are locked at a time, reducing the likelihood of lock contention. Additionally, switching from parallel to serial processing mode can help prevent row locks, as it ensures batches are processed one after the other rather than concurrently.
- Manage Data Skew: Data skew happens when a single Salesforce record (like an account) has a very high number of child records. This can lead to performance issues and row locking errors. If you detect data skew (typically more than 10,000 child records for a single parent record), consider splitting the parent record into multiple records and distributing the child records among them.
- Code Optimization: Review and optimize your Apex code to ensure it’s efficient. Sometimes, changing certain functionalities to asynchronous processing can help reduce the risk of row locks.
- Sort Records Based on Parent Record: When processing records in batches, especially in parallel mode, try to sort the records based on their parent record. This approach reduces the chance of different child records of the same parent being processed in different batches, which can lead to row locks.
- Consider Transaction Duration: Remember that Salesforce locks are typically short-lived, lasting only a few seconds. However, a transaction will timeout if it waits more than 10 seconds for a lock to be released. Design your transactions to complete within this timeframe to avoid lock timeouts.
By implementing these strategies, you can significantly reduce the occurrence of row locks in your Salesforce Apex batch processing, leading to smoother and more efficient operations.
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