A debug log can record database operations, system processes, and errors that occur when executing a transaction or running unit tests. Debug logs can contain information about:
Database changes
HTTP callouts
Apex errors
Resources used by Apex
Automated workflow processes, such as:
The debug log doesn’t include information from actions triggered by time-based workflows. It also doesn’t include information from standard or custom controllers used in Visualforce email templates.
Note
You can retain and manage debug logs for specific users, including yourself, and for classes and triggers. Setting class and trigger trace flags doesn’t cause logs to be generated or saved. Class and trigger trace flags override other logging levels, including logging levels set by user trace flags, but they don’t cause logging to occur. If logging is enabled when classes or triggers execute, logs are generated at the time of execution.
To view a debug log from Setup, enter Debug Logs in the Quick Find box, then select Debug Logs. Then click View next to the debug log that you want to examine. Click Download to download the debug log as a log file.
Debug logs have the following limits.
Each debug log must be 20 MB or smaller. Debug logs that are larger than 20 MB are reduced in size by removing older log lines, such as log lines for earlier System.debug statements. The log lines can be removed from any location, not just the start of the debug log.
System debug logs are retained for 24 hours. Monitoring debug logs are retained for seven days.
If you generate more than 1,000 MB of debug logs in a 15-minute window, your trace flags are disabled. We send an email to the users who last modified the trace flags, informing them that they can re-enable the trace flag in 15 minutes.
If the debug log trace flag is enabled on a frequently accessed Apex class or for a user executing requests often, the request can result in failure, regardless of the time window and the size of the debug logs.
Warning
When your org accumulates more than 1,000 MB of debug logs, we prevent users in the org from adding or editing trace flags. To add or edit trace flags so that you can generate more logs after you reach the limit, delete some debug logs.
After you generate a debug log, the type and amount of information listed depends on the filter values you set for the user. However, the format for a debug log is always the same.
Session IDs are replaced with “SESSION_ID_REMOVED” in Apex debug logs
Note
A debug log has the following sections.
Header: The header contains the following information.
The following is an example of a header.
168.0 APEX_CODE,DEBUG;APEX_PROFILING,INFO;CALLOUT,INFO;DB,INFO;SYSTEM,DEBUG;VALIDATION,INFO;VISUALFORCE,INFO;
2WORKFLOW,INFOIn this example, the API version is 68.0, and the following debug log categories and levels have been set.
| Apex Code | DEBUG |
| Apex Profiling | INFO |
| Callout | INFO |
| Database | INFO |
| System | DEBUG |
| Validation | INFO |
| Visualforce | INFO |
| Workflow | INFO |
If the Apex Code log level is set to FINEST, the debug log includes details of all Apex variable assignments. Ensure that the Apex Code being traced doesn’t handle sensitive data. Before enabling FINEST log level, be sure to understand the level of sensitive data your organization’s Apex handles. Be careful with processes such as community users self-registration where user passwords can be assigned to an Apex string variable.
Warning
Execution Units: An execution unit is equivalent to a transaction. It contains everything that occurred within the transaction. EXECUTION_STARTED and EXECUTION_FINISHED delimit an execution unit.
Code Units: A code unit is a discrete unit of work within a transaction. For example, a trigger is one unit of code, as is a webservice method or a validation rule.
A class isn’t a discrete unit of code.
Note
CODE_UNIT_STARTED and CODE_UNIT_FINISHED delimit units of code. Units of work can embed other units of work. For example:
1EXECUTION_STARTED
2CODE_UNIT_STARTED|[EXTERNAL]execute_anonymous_apex
3CODE_UNIT_STARTED|[EXTERNAL]MyTrigger on Account trigger event BeforeInsert for [new]|__sfdc_trigger/MyTrigger
4CODE_UNIT_FINISHED <-- The trigger ends
5CODE_UNIT_FINISHED <-- The executeAnonymous ends
6EXECUTION_FINISHEDUnits of code include, but aren’t limited to, the following:
@future method invocationsexecuteAnonymous callsstart and finish methods, and each execution of the execute methodSystem.Schedule execute methodLog Lines: Log lines are included inside units of code and indicate which code or rules are being executed. Log lines can also be messages written to the debug log. Log lines are made up of a set of fields, delimited by a pipe (|). The format is:
timestamp: Consists of the time when the event occurred and a value between parentheses. The time is in the user’s time zone and in the format HH:mm:ss.SSS. The value in parentheses represents the time elapsed in nanoseconds since the start of the request. The elapsed time value is excluded from logs reviewed in the Developer Console when you use the Execution Log view. However, you can see the elapsed time when you use the Raw Log view. To open the Raw Log view, from the Developer Console’s Logs tab, right-click the name of a log and select Open Raw Log.
event identifier: Specifies the event that triggered the debug log entry (such as SAVEPOINT_RESET or VALIDATION_RULE).
Also includes additional information logged with that event, such as the method name or the line and character number where the code was executed. If a line number can’t be located, [EXTERNAL] is logged instead. For example, [EXTERNAL] is logged for built-in Apex classes or code that’s in a managed package.
For some events (CODE_UNIT_STARTED, CODE_UNIT_FINISHED, VF_APEX_CALL_START, VF_APEX_CALL_END, CONSTRUCTOR_ENTRY, and CONSTRUCTOR_EXIT), the end of the event identifier includes a pipe (|) followed by a typeRef for an Apex class or trigger.
For a trigger, the typeRef begins with the SFDC trigger prefix __sfdc_trigger/. For example, __sfdc_trigger/YourTriggerName or __sfdc_trigger/YourNamespace/YourTriggerName.
For a class, the typeRef uses the format YourClass, YourClass$YourInnerClass, or YourNamespace/YourClass$YourInnerClass.
More Log Data: In addition, the log contains the following information.
executeAnonymous, batch Apex message processing, @future methods, Apex test methods, Apex web service methods, and Apex lead convert.The following is an example debug log.
137.0 APEX_CODE,FINEST;APEX_PROFILING,INFO;CALLOUT,INFO;DB,INFO;SYSTEM,DEBUG;
2 VALIDATION,INFO;VISUALFORCE,INFO;WORKFLOW,INFO
3Execute Anonymous: System.debug('Hello World!');
416:06:58.18 (18043585)|USER_INFO|[EXTERNAL]|005D0000001bYPN|devuser@example.org|
5 Pacific Standard Time|GMT-08:00
616:06:58.18 (18348659)|EXECUTION_STARTED
716:06:58.18 (18383790)|CODE_UNIT_STARTED|[EXTERNAL]|execute_anonymous_apex
816:06:58.18 (23822880)|HEAP_ALLOCATE|[72]|Bytes:3
916:06:58.18 (24271272)|HEAP_ALLOCATE|[77]|Bytes:152
1016:06:58.18 (24691098)|HEAP_ALLOCATE|[342]|Bytes:408
1116:06:58.18 (25306695)|HEAP_ALLOCATE|[355]|Bytes:408
1216:06:58.18 (25787912)|HEAP_ALLOCATE|[467]|Bytes:48
1316:06:58.18 (26415871)|HEAP_ALLOCATE|[139]|Bytes:6
1416:06:58.18 (26979574)|HEAP_ALLOCATE|[EXTERNAL]|Bytes:1
1516:06:58.18 (27384663)|STATEMENT_EXECUTE|[1]
1616:06:58.18 (27414067)|STATEMENT_EXECUTE|[1]
1716:06:58.18 (27458836)|HEAP_ALLOCATE|[1]|Bytes:12
1816:06:58.18 (27612700)|HEAP_ALLOCATE|[50]|Bytes:5
1916:06:58.18 (27768171)|HEAP_ALLOCATE|[56]|Bytes:5
2016:06:58.18 (27877126)|HEAP_ALLOCATE|[64]|Bytes:7
2116:06:58.18 (49244886)|USER_DEBUG|[1]|DEBUG|Hello World!
2216:06:58.49 (49590539)|CUMULATIVE_LIMIT_USAGE
2316:06:58.49 (49590539)|LIMIT_USAGE_FOR_NS|(default)|
24 Number of SOQL queries: 0 out of 100
25 Number of query rows: 0 out of 50000
26 Number of SOSL queries: 0 out of 20
27 Number of DML statements: 0 out of 150
28 Number of DML rows: 0 out of 10000
29 Maximum CPU time: 0 out of 10000
30 Maximum heap size: 0 out of 10000000
31 Number of callouts: 0 out of 100
32 Number of Email Invocations: 0 out of 10
33 Number of future calls: 0 out of 50
34 Number of queueable jobs added to the queue: 0 out of 50
35 Number of Mobile Apex push calls: 0 out of 10
36
3716:06:58.49 (49590539)|CUMULATIVE_LIMIT_USAGE_END
38
3916:06:58.18 (52417923)|CODE_UNIT_FINISHED|execute_anonymous_apex
4016:06:58.18 (54114689)|EXECUTION_FINISHEDTo debug complex Apex logic, you can set Apex class and trigger trace flags, also known as debug log filters. For example, you can raise the log verbosity for a given class while turning off logging for other classes or triggers. These trace flags have the debug log type CLASS_TRACING and override the debug log levels of the USER_DEBUG and DEVELOPER_LOG trace flags.
For an explanation and an example of how Apex class and trigger trace flags work, see Debug Log Filtering for Apex Classes and Apex Triggers in Salesforce Help.
For concrete instructions about how to configure debug log filters, see Set Up Apex Class and Trigger Trace Flags in Salesforce Help.
Working with Logs in the Developer Console
Use the Logs tab in the Developer Console to open debug logs.
Which events are logged depends on various factors. These factors include your trace flags, the default logging levels, your API header, user-based system log enablement, and the log levels set by your entry points.
See Also
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