Understanding Apex Runtime and Constraints

Governor Limits and Multitenancy

Apex enforces strict per-transaction limits to ensure fair use in a multitenant environment. These include limits on SOQL queries, DML operations, CPU time, heap size, and more.

Trigger Lifecycle and Order of Execution

Triggers in Apex follow a specific order of operations that includes validation rules, workflow rules, and after triggers. Misplaced logic can cause unexpected behaviors or recursive executions.

Common Apex Issues in Large-Scale Projects

1. Hitting Governor Limits

Frequent errors include Too many SOQL queries: 101, Too many DML statements: 151, or heap size overflows.

System.LimitException: Too many SOQL queries: 101
  • Use bulkified code (process lists instead of single records).
  • Use Maps to reduce redundant queries.
  • Move expensive logic to asynchronous contexts when possible.

2. Recursive Trigger Execution

When DML operations in a trigger cause the same trigger to fire again, infinite loops can occur unless guard logic is used.

if (!TriggerHelper.hasFired) {
    TriggerHelper.hasFired = true;
    // Perform logic
}

3. Low or Incomplete Test Coverage

Deployment to production requires 75% coverage. Complex logic with multiple branches often lacks full test coverage.

  • Use Test.startTest() and Test.stopTest() to isolate governor usage.
  • Ensure test methods cover all decision paths, including exceptions and validation rules.

4. Field-Level Security or Sharing Rule Violations

Code that runs in system context may inadvertently bypass sharing or visibility constraints. Conversely, without with sharing, logic may access unintended records.

5. Deployment Failures and Metadata Conflicts

Deployments via change sets or CI/CD tools like Gearset may fail due to dependency mismatches, missing test coverage, or stale metadata.

Diagnostics and Debugging Techniques

Use Developer Console and Debug Logs

Enable debug logs for the executing user to trace Apex execution, SOQL, and DML operations. Use checkpoints to inspect object state.

Leverage Limits Methods

Insert diagnostic logs using Apex Limits methods to track usage.

System.debug('SOQL Queries Used: ' + Limits.getQueries());

Utilize Test.runAs and SeeAllData=false

Isolate test context using runAs for user-specific logic and prevent data leakage using SeeAllData=false.

Monitor with Salesforce Setup Tools

Use Setup → Apex Jobs, Scheduled Jobs, and Apex Test Execution dashboards to view background failures and job logs.

Step-by-Step Resolution Guide

1. Refactor for Bulkification

Replace single-record processing with for (SObject obj : Trigger.new) blocks. Use Maps and Sets to aggregate logic.

2. Prevent Recursive Trigger Logic

Implement static Boolean flags or use a trigger handler framework with context checks.

3. Improve Test Coverage and Reliability

Write unit tests for all branches. Use mock data factories to isolate dependencies and repeat test setup across test methods.

4. Enforce Proper Sharing Behavior

Mark classes as with sharing where appropriate. Use stripInaccessible() to ensure field-level security compliance.

5. Resolve Deployment Errors

Use deployment validation runs. Compare org metadata using version control tools and synchronize profile/permission dependencies explicitly.

Best Practices for Enterprise Apex Development

  • Adopt trigger frameworks (e.g., fflib, Apex Common) to decouple logic.
  • Use Custom Metadata Types instead of hardcoding config values.
  • Implement Apex PMD or CodeScan for static analysis and standards enforcement.
  • Leverage Platform Events or Queueable Apex for asynchronous processing.
  • Enforce CI/CD discipline with org diffs and test automation on pull requests.

Conclusion

Apex development at scale requires deep understanding of Salesforce governor limits, data sharing rules, and platform lifecycle. By structuring code for bulk execution, improving test coverage, and leveraging Salesforce's diagnostic tools, teams can create robust, secure, and maintainable Apex solutions. Troubleshooting Apex effectively requires not only debugging logic but also architectural discipline aligned with the multitenant nature of the Salesforce platform.

FAQs

1. How can I avoid hitting SOQL query limits?

Use bulkified logic, query outside loops, and consolidate queries using Maps keyed by IDs.

2. Why is my trigger causing an infinite loop?

DML inside a trigger is recursively firing the same trigger. Add static guards or split logic into future/queueable methods.

3. What causes low code coverage in Apex tests?

Unexecuted branches, lack of negative test cases, or missing exception handling paths. Improve input diversity and conditional logic in tests.

4. How do I secure Apex from field-level access issues?

Use Security.stripInaccessible() and always respect CRUD/FLS in your logic, especially for managed packages or ISV apps.

5. What tools can I use to monitor Apex jobs?

Use Apex Jobs in Setup, `System.schedule()` logs, and Debug Log Traces. For asynchronous Apex, monitor Scheduled and Queueable job history.