afv-library/skills/platform-apex-logs-debug/references/debug-log-reference.md

Salesforce Debug Log Reference

Log Structure

Debug logs follow a consistent format:

TIMESTAMP|EVENT_IDENTIFIER|[PARAMS]|DETAILS

Example:

14:32:54.123 (123456789)|SOQL_EXECUTE_BEGIN|[45]|SELECT Id FROM Account

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Event Categories

Execution Events

Event	Description	Analysis Notes
EXECUTION_STARTED	Transaction begins	Identifies transaction type
EXECUTION_FINISHED	Transaction ends	Total execution time
CODE_UNIT_STARTED	Method/trigger entry	Call stack tracing
CODE_UNIT_FINISHED	Method/trigger exit	Method duration

SOQL Events

Event	Description	Key Fields
SOQL_EXECUTE_BEGIN	Query starts	Line number, Query text
SOQL_EXECUTE_END	Query ends	Rows returned

Analysis Pattern:

|SOQL_EXECUTE_BEGIN|[45]|SELECT Id, Name FROM Account WHERE...
|SOQL_EXECUTE_END|[3 rows]

• Line 45 in source code
• Query returned 3 rows

Warning Signs:

• Same query appearing multiple times → SOQL in loop
• [100000 rows] → Non-selective query
• Query without WHERE clause → Full table scan

DML Events

Event	Description	Key Fields
DML_BEGIN	DML starts	Line number, Operation type, Object
DML_END	DML ends	Rows affected

Analysis Pattern:

|DML_BEGIN|[78]|Op:Insert|Type:Contact|
|DML_END|[200 rows]

• Line 78: INSERT operation
• 200 Contact records inserted

Warning Signs:

• Same DML operation appearing multiple times → DML in loop
• DML after each SOQL → Likely unbulkified code

Limit Events

Event	Description	Format
LIMIT_USAGE	Current limit usage	`LIMIT_NAME
LIMIT_USAGE_FOR_NS	Per-namespace limits	`LIMIT_NAME
CUMULATIVE_LIMIT_USAGE	End of transaction	Summary of all limits

Example:

|LIMIT_USAGE|SOQL_QUERIES|25|100
|LIMIT_USAGE|DML_STATEMENTS|45|150
|LIMIT_USAGE|CPU_TIME|3500|10000
|LIMIT_USAGE|HEAP_SIZE|2500000|6000000

Exception Events

Event	Description	Format
EXCEPTION_THROWN	Exception occurs	`[line]
FATAL_ERROR	Unhandled exception	Full stack trace

Analysis Pattern:

|EXCEPTION_THROWN|[67]|System.NullPointerException|Attempt to de-reference a null object
|FATAL_ERROR|System.NullPointerException: Attempt to de-reference a null object
  Class.ContactService.processContacts: line 67, column 1
  Class.AccountTriggerHandler.afterUpdate: line 34, column 1
  Trigger.AccountTrigger: line 5, column 1

Method Events

Event	Description	Use Case
METHOD_ENTRY	Method called	Call hierarchy
METHOD_EXIT	Method returns	Method duration
CONSTRUCTOR_ENTRY	Constructor called	Object creation
CONSTRUCTOR_EXIT	Constructor returns

Loop Events

Event	Description	Important For
LOOP_BEGIN	Loop starts	SOQL/DML in loop detection
LOOP_END	Loop ends
ITERATION_BEGIN	Loop iteration	Iteration count
ITERATION_END	Iteration ends

Detection Pattern for SOQL in Loop:

|LOOP_BEGIN|
  |ITERATION_BEGIN|
    |SOQL_EXECUTE_BEGIN|[45]|SELECT...
    |SOQL_EXECUTE_END|[1 rows]
  |ITERATION_END|
  |ITERATION_BEGIN|
    |SOQL_EXECUTE_BEGIN|[45]|SELECT...  ← Same query repeating!
    |SOQL_EXECUTE_END|[1 rows]
  |ITERATION_END|
|LOOP_END|

Callout Events

Event	Description	Key Fields
CALLOUT_EXTERNAL_ENTRY	HTTP callout starts	Endpoint URL
CALLOUT_EXTERNAL_EXIT	HTTP callout ends	Status code, Duration

Example:

|CALLOUT_EXTERNAL_ENTRY|[89]|https://api.example.com/endpoint
|CALLOUT_EXTERNAL_EXIT|[200]|[1500ms]

Heap Events

Event	Description	Importance
HEAP_ALLOCATE	Heap allocation	Track large allocations
HEAP_DEALLOCATE	Heap freed	Garbage collection

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Log Levels

Categories and Levels

Category	What It Controls
Database	SOQL, SOSL, DML
Workflow	Workflow rules, Process Builder
Validation	Validation rules
Callout	HTTP callouts
Apex Code	Apex execution
Apex Profiling	Method timing
Visualforce	VF page execution
System	System operations

Level Values

Level	Amount of Detail	Use Case
NONE	Nothing	Disable category
ERROR	Errors only	Production monitoring
WARN	Warnings + errors
INFO	General info	Default
DEBUG	Detailed debug	Development
FINE	Very detailed	Deep debugging
FINER	Method entry/exit	Performance analysis
FINEST	Everything	Complete trace

Recommended Debug Level Settings

For Performance Issues:

Apex Code: FINE
Apex Profiling: FINEST
Database: FINE
System: DEBUG

For Exception Debugging:

Apex Code: DEBUG
Apex Profiling: FINE
Database: INFO
System: DEBUG

For Callout Issues:

Apex Code: DEBUG
Callout: FINEST
System: DEBUG

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Governor Limits Reference

Synchronous Limits

Limit	Value	Log Event
SOQL Queries	100	SOQL_QUERIES
SOQL Rows	50,000	SOQL_ROWS
DML Statements	150	DML_STATEMENTS
DML Rows	10,000	DML_ROWS
CPU Time	10,000 ms	CPU_TIME
Heap Size	6 MB	HEAP_SIZE
Callouts	100	CALLOUTS
Future Calls	50	FUTURE_CALLS

Asynchronous Limits

Limit	Value	Applies To
CPU Time	60,000 ms	@future, Batch, Queueable
Heap Size	12 MB	@future, Batch, Queueable

Warning Thresholds

Limit	Warning (80%)	Critical (95%)
SOQL Queries	80	95
DML Statements	120	143
CPU Time	8,000 ms	9,500 ms
Heap Size	4.8 MB	5.7 MB

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Common Log Patterns

Pattern 1: SOQL in Loop

|LOOP_BEGIN|
|ITERATION_BEGIN|
|SOQL_EXECUTE_BEGIN|[45]|SELECT Id FROM Contact WHERE AccountId = '001xxx'
|SOQL_EXECUTE_END|[1 rows]
|ITERATION_END|
|ITERATION_BEGIN|
|SOQL_EXECUTE_BEGIN|[45]|SELECT Id FROM Contact WHERE AccountId = '001yyy'
|SOQL_EXECUTE_END|[1 rows]
|ITERATION_END|
... (repeats 100 times)
|LIMIT_USAGE|SOQL_QUERIES|100|100  ← LIMIT HIT!
|FATAL_ERROR|System.LimitException: Too many SOQL queries: 101

Pattern 2: DML in Loop

|LOOP_BEGIN|
|ITERATION_BEGIN|
|DML_BEGIN|[78]|Op:Insert|Type:Contact|
|DML_END|[1 rows]
|ITERATION_END|
... (repeats 150 times)
|LIMIT_USAGE|DML_STATEMENTS|150|150  ← LIMIT HIT!
|FATAL_ERROR|System.LimitException: Too many DML statements: 151

Pattern 3: Non-Selective Query

|SOQL_EXECUTE_BEGIN|[23]|SELECT Id FROM Lead WHERE Status = 'Open'
|SOQL_EXECUTE_END|[250000 rows]  ← Large result set!

Pattern 4: CPU Limit Approaching

|CUMULATIVE_LIMIT_USAGE|
|CPU_TIME|9500|10000  ← 95% used!

Pattern 5: Null Pointer Exception

|SOQL_EXECUTE_BEGIN|[45]|SELECT Id FROM Account WHERE Id = '001xxx'
|SOQL_EXECUTE_END|[0 rows]  ← No results!
|METHOD_EXIT|getAccount|
|EXCEPTION_THROWN|[47]|System.NullPointerException|Attempt to de-reference a null object

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Log Analysis Checklist

Quick Scan

1. Search for FATAL_ERROR - Find the exception
2. Search for LIMIT_USAGE - Check governor limits
3. Search for SOQL_EXECUTE_BEGIN - Count queries
4. Search for DML_BEGIN - Count DML operations
5. Search for LOOP_BEGIN - Check for operations in loops

Deep Analysis

1. Trace the call stack - Use CODE_UNIT_STARTED events
2. Find the hotspot - Use Apex Profiling: FINEST for method timing
3. Identify large queries - Look for [N rows] in SOQL_EXECUTE_END
4. Check callout timing - Look for slow CALLOUT_EXTERNAL_EXIT
5. Monitor heap growth - Track HEAP_ALLOCATE events

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Related Commands

Command	Purpose
sf apex list log	List available logs
sf apex get log --log-id XXX	Download specific log
sf apex tail log	Stream logs real-time
sf data delete record --sobject ApexLog --record-id <id>	Delete individual log record

See cli-commands.md for detailed command reference.