Trigger Selection Analysis

Requirements Analysis:

• Execution schedule: Daily at 2 AM
• Critical requirement: If the trigger stops and restarts, the next execution must occur at the next scheduled 2 AM time
• Key consideration: Behavior after trigger restart

Trigger Type Comparison:

A. Schedule Trigger

• Pros: Simple to configure for daily execution at specific times
• Cons: Does NOT maintain state after restart; if stopped and restarted, it will execute immediately rather than waiting for the next scheduled time
• Restart behavior: Executes immediately upon restart, potentially missing the intended 2 AM schedule

B. Tumbling Window Trigger ✓

• Pros:
  • Maintains state and schedule integrity
  • If stopped and restarted, it resumes execution at the next scheduled window boundary
  • For daily execution, configure with 24-hour window size
  • Ensures exactly one execution per day at the specified time
• Restart behavior: After restart, waits for the next 2 AM window rather than executing immediately

C. Storage Event Trigger

• Not applicable: Event-based trigger that responds to storage events, not scheduled execution

D. Custom Event Trigger

• Not applicable: Event-based trigger that responds to custom events, not scheduled execution

Why Tumbling Window is Optimal:

The tumbling window trigger's stateful nature ensures that after a restart, it calculates the next appropriate execution time based on the original schedule. This prevents immediate execution upon restart and maintains the intended daily 2 AM cadence. The trigger "remembers" its position in the execution sequence and resumes accordingly.

Why Schedule Trigger is Less Suitable:

While schedule triggers work well for simple recurring patterns, they lack the state persistence needed for the restart requirement. A restarted schedule trigger would execute immediately rather than waiting for the next 2 AM slot, potentially causing unwanted executions and disrupting the daily schedule.

Configuration Recommendation:

Configure the tumbling window trigger with:

• Window size: 24 hours
• Start time: 2 AM
• Frequency: Daily
• Max concurrency: 1 (to ensure only one instance runs at a time)