Understanding Apex Execution Flow

Whenever Apex runs, Salesforce executes it inside a transaction.

A transaction includes:
● Code execution
● Database operations
● Validation rules
● Triggers
● Workflows / Flows
● Commit or rollback

If any error occurs:
● Entire transaction rolls back
● No partial data is saved

This ensures data consistency.

Synchronous vs Asynchronous Execution

◆ Synchronous Apex

Runs immediately and blocks the user until completion.

Examples:
● Button click
● LWC imperative call
● Trigger execution

Characteristics:
● Fast response required
● Limited CPU time
● User waits for completion

◆ Asynchronous Apex

Runs in the background.

Examples:
● Future methods
● Queueable Apex
● Batch Apex
● Scheduled jobs

Characteristics:
● Longer processing allowed
● No UI blocking
● Better for heavy workloads

We’ll cover async in depth later in the roadmap.

What Are Debug Logs?

Debug logs capture everything that happens during Apex execution.

They show:
● Method calls
● Variable values
● SOQL queries
● DML operations
● Exceptions
● Limits usage

Logs are your primary debugging tool.

Enable Debug Logs for Your User

Method - Salesforce Setup

1. Open Salesforce.

2. Go to Setup.

3. Search for:

Debug Logs

4. Click New.

5. Select your user.

6. Set log levels (use default initially).

7. Save.

Now all Apex executions for your user will generate logs.

Execute Code to Generate Logs

You can generate logs by:
● Running Execute Anonymous Apex
● Triggering UI actions
● Calling Apex from LWC
● Running tests

Example Execute Anonymous:

System.debug('Debugging Apex');

Execute it and check logs.

How to Read Debug Logs

Debug logs can be large and overwhelming.

Focus on:
● USER_DEBUG → Your debug statements
● EXCEPTION_THROWN → Errors
● SOQL_EXECUTE_BEGIN → Queries
● DML_BEGIN → Database operations
● LIMIT_USAGE → Governor limits

Search inside logs instead of scrolling.

Using System.debug Effectively

System.debug prints messages into logs.

Example:

Integer total = 10;
System.debug('Total value = ' + total);

Best practices:
● Log meaningful values
● Avoid excessive logging in production
● Use clear messages
● Remove debug statements after debugging

Conclusion

Debugging and productivity skills separate beginners from professional developers.

By mastering:
● Execution flow
● Debug logs
● System.debug
● Performance monitoring

You’ll build stable and scalable Apex solutions.

Keep Building!

Apex Beginner to Advance

Debug Logs, Execution Flow & Productivity