Scheduled Tasks

Scheduled Tasks

Moodle uses a task scheduling system to run background operations at specified intervals. The scheduled task system replaced the older event-based cron system and provides granular control over when and how tasks execute.

Viewing Scheduled Tasks

Navigate to Site administration > Server > Scheduled tasks to see all registered tasks. The table displays:

• Task name: The human-readable name and the PHP class name
• Component: The plugin or core component that owns the task
• Schedule: When the task is configured to run (minute, hour, day, month, day of week)
• Last run: Timestamp of the last successful execution
• Next run: When the task is scheduled to run next
• Running: Whether the task is currently executing
• Fail delay: Exponential backoff delay if the task has been failing

Task Schedule Format

Tasks use a cron-like schedule format with five fields:

Minute (0-59)
Hour (0-23)
Day of Month (1-31)
Month (1-12)
Day of Week (0-6, where 0 = Sunday)

Special values:

• * — Every value (e.g., every minute, every hour)
• */5 — Every 5th value (e.g., every 5 minutes)
• 1,15 — Specific values (1st and 15th minute)
• R — Random value within the range (Moodle-specific; useful for distributing load)

Editing Task Schedules

Click the edit icon next to a task to modify its schedule. You can change the minute, hour, day, month, and day of week fields. You can also:

• Disable the task: Prevents the task from running via cron
• Reset to default: Restores the task to its original schedule

Common Scheduled Tasks

Key tasks that run in a typical Moodle installation:

• core asksend_new_user_passwords_task — Sends password notifications to new users
• core asksend_failed_login_notifications_task — Sends failed login alerts
• core askcron_task — Legacy cron task for backward compatibility
• core asksession_cleanup_task — Cleans up expired sessions
• core askfile_trash_cleanup_task — Removes deleted files from trash
• core askcache_cleanup_task — Cleans up expired cache entries
• core askautomated_backup_task — Runs automated course backups
• core askstats_cron_task — Processes site statistics
• core askcompletion_regular_task — Recalculates activity completion
• core askadges_cron_task — Processes badge criteria and awards
• core askgrade_cron_task — Recalculates grades
• mod_forum asksend_user_digests — Sends forum digest emails

Running Tasks via CLI

Execute a specific task immediately from the command line:

# Run a specific task
sudo -u www-data php admin/cli/scheduled_task.php 
  --execute=\core\task\automated_backup_task

# List all tasks and their status
sudo -u www-data php admin/cli/scheduled_task.php --list

# Show the status of a specific task
sudo -u www-data php admin/cli/scheduled_task.php 
  --showsql --execute=\core\task\stats_cron_task

Ad Hoc Tasks

In addition to scheduled tasks, Moodle uses ad hoc tasks for one-time operations that need to run in the background. These include:

• Sending individual email notifications
• Processing assignment submission events
• Course backup operations
• Content indexing for global search

Ad hoc tasks are stored in the mdl_task_adhoc table and processed during each cron run. You can view pending ad hoc tasks with:

SELECT classname, COUNT(*) as pending 
FROM mdl_task_adhoc 
GROUP BY classname 
ORDER BY pending DESC;

Task Logs

Moodle logs task execution results. View task logs at Site administration > Server > Task logs. The logs show:

• Task name and type (scheduled or ad hoc)
• Start and end time
• Duration
• Result (success or failure)
• Output and error messages
• Database reads and writes

Troubleshooting Task Issues

• Task stuck "running": If a task shows as running for an unusually long time, it may have crashed. Reset the running flag in the database or wait for the lock to expire.
• Fail delay increasing: When a task fails repeatedly, Moodle applies an exponential backoff delay (1 min, 2 min, 4 min, etc., up to 24 hours). Fix the underlying issue, then reset the fail delay by editing the task.
• Tasks not running at all: Verify that cron is properly configured and running every minute.