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Cron Jobs

Cron jobs are scheduled tasks that run automatically in Paideia LMS. The admin cron jobs page provides comprehensive visibility into job execution history, allowing administrators to track job execution patterns, debug failures, and monitor system performance.

Overview

Section titled “Overview”

The cron jobs feature provides administrators with:

  • Job History: View execution history of all cron jobs
  • Status Monitoring: See which jobs succeeded or failed
  • Error Details: View detailed error messages for failed jobs
  • Execution Tracking: Monitor job execution timestamps and patterns

Accessing Cron Jobs

Section titled “Accessing Cron Jobs”

To access the cron jobs page:

  1. Log in as an administrator
  2. Navigate to Admin → Server → Cron jobs

You’ll see a comprehensive view of all cron jobs and their execution history.

Job History Display

Section titled “Job History Display”

The job history table displays detailed information about job executions:

Table Columns

Section titled “Table Columns”
  • Job Name: The name of the job (derived from task slug or queue)
  • Task Slug: The task identifier
  • Queue: The queue name
  • Executed At: When the job started execution
  • Completed At: When the job finished execution
  • State: Job execution status (Succeeded or Failed)
  • Error: Error message for failed jobs

Status Indicators

Section titled “Status Indicators”
  • Green Badge: Job succeeded
  • Red Badge: Job failed

Error Display

Section titled “Error Display”

Failed jobs display detailed error information:

  • Formatted Display: Errors are displayed using CodeHighlight component
  • Copy Functionality: Easy to copy error messages for further analysis
  • Format Support: Supports both string and JSON error formats
  • Readable Format: Errors are formatted for better readability

Understanding Job Execution

Section titled “Understanding Job Execution”

Successful Jobs

Section titled “Successful Jobs”

Successful jobs show:

  • Green status badge
  • Execution timestamps
  • Completion timestamp
  • No error message

Failed Jobs

Section titled “Failed Jobs”

Failed jobs show:

  • Red status badge
  • Execution timestamps
  • Completion timestamp (if available)
  • Detailed error message

Database Integration

Section titled “Database Integration”

Job history is retrieved directly from the database:

  • Source Tables: payload_jobs and payload_jobs_log
  • Query Method: Uses Drizzle ORM for database queries
  • Left Join: Includes all jobs, even when log entries don’t exist
  • Fallback Logic: Handles cases where logs may not exist

PostgreSQL Behavior

Section titled “PostgreSQL Behavior”

PostgreSQL only creates log entries in payload_jobs_log for failed jobs. The query uses a left join to ensure all jobs are included in the history, even when log entries don’t exist.

History Limit

Section titled “History Limit”

The job history is limited to prevent performance issues:

  • Default Limit: 100 entries
  • Sorting: Most recent jobs first
  • Configurable: Limit can be adjusted in the function

Common Use Cases

Section titled “Common Use Cases”

Monitoring Job Execution

Section titled “Monitoring Job Execution”

Use the job history to:

  • Track job execution patterns over time
  • Identify jobs that fail frequently
  • Monitor system performance
  • Understand job execution status

Debugging Failed Jobs

Section titled “Debugging Failed Jobs”

When a job fails:

  1. Check the job history table
  2. Find the failed job (red badge)
  3. Review the error message
  4. Copy the error for further analysis
  5. Investigate the root cause

Performance Monitoring

Section titled “Performance Monitoring”

Monitor job execution to:

  • Identify slow-running jobs
  • Track job execution frequency
  • Monitor system load
  • Optimize job scheduling

Best Practices

Section titled “Best Practices”

Regular Monitoring

Section titled “Regular Monitoring”
  • Check job history regularly
  • Monitor for failed jobs
  • Review error messages
  • Track execution patterns

Error Analysis

Section titled “Error Analysis”
  • Copy error messages for analysis
  • Review error details carefully
  • Check system logs for additional context
  • Investigate root causes

Performance Optimization

Section titled “Performance Optimization”
  • Monitor job execution times
  • Identify slow-running jobs
  • Optimize job scheduling
  • Adjust job frequency if needed

Troubleshooting

Section titled “Troubleshooting”

Jobs Not Appearing in History

Section titled “Jobs Not Appearing in History”

If jobs don’t appear in history:

  1. Check that jobs are actually running
  2. Verify database connectivity
  3. Check system logs for errors
  4. Verify job configuration

Missing Log Entries

Section titled “Missing Log Entries”

If log entries are missing:

  • This is normal for successful jobs in PostgreSQL
  • The system uses fallback logic to show job information
  • Check the payload_jobs table directly if needed

Error Messages Not Displaying

Section titled “Error Messages Not Displaying”

If error messages aren’t displaying:

  1. Check that the job actually failed
  2. Verify error format (string or JSON)
  3. Check browser console for errors
  4. Verify CodeHighlight component is working
Section titled “Related Features”
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