What is Fixed Rate?
A scheduling mode that runs jobs at exact intervals regardless of how long each execution takes.
Definition
Fixed rate scheduling triggers executions at a constant interval measured from the start of each run, not the end. If a job is configured with a 5-minute fixed rate, it starts every 5 minutes regardless of whether the previous execution has finished. If an execution takes longer than the interval, multiple instances may run concurrently. This provides predictable, clock-aligned timing but requires overlap handling.
Simple Analogy
Like a train schedule where trains depart every 10 minutes on the dot — the next train leaves on time regardless of whether the previous one has arrived at its destination.
Why It Matters
Fixed rate scheduling ensures consistent timing, which is essential for tasks that must run at predictable intervals: health checks, metrics collection, and SLA-bound reporting. However, without overlap protection, long-running executions can cause concurrency issues. Understanding fixed rate versus fixed delay helps you choose the right scheduling mode.
How to Verify
Review your execution history timestamps. If start times are evenly spaced regardless of execution durations, you have fixed rate scheduling. Check for overlapping executions in your logs — they indicate the job sometimes takes longer than the interval.
Common Mistakes
Using fixed rate without overlap protection, allowing multiple instances to run simultaneously and fight over shared resources. Not monitoring execution duration relative to the interval — if execution regularly exceeds the interval, jobs pile up. Confusing fixed rate with cron scheduling — cron is calendar-based, not interval-based.
Best Practices
Use fixed rate when exact periodicity matters more than overlap avoidance. Always combine fixed rate scheduling with a concurrency policy — either skip the new execution if the previous is still running, or queue it. Monitor execution duration trends and alert before they approach the interval length.
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Try it free →Frequently Asked Questions
What is Fixed Rate?
Fixed rate scheduling triggers executions at a constant interval measured from the start of each run, not the end. If a job is configured with a 5-minute fixed rate, it starts every 5 minutes regardless of whether the previous execution has finished. If an execution takes longer than the interval, multiple instances may run concurrently. This provides predictable, clock-aligned timing but requires overlap handling.
Why does Fixed Rate matter for cron jobs?
Fixed rate scheduling ensures consistent timing, which is essential for tasks that must run at predictable intervals: health checks, metrics collection, and SLA-bound reporting. However, without overlap protection, long-running executions can cause concurrency issues. Understanding fixed rate versus fixed delay helps you choose the right scheduling mode.
What are best practices for Fixed Rate?
Use fixed rate when exact periodicity matters more than overlap avoidance. Always combine fixed rate scheduling with a concurrency policy — either skip the new execution if the previous is still running, or queue it. Monitor execution duration trends and alert before they approach the interval length.
Related Terms
Fixed Delay
A scheduling mode that waits a fixed time after the previous execution finishes before starting the next.
Interval
The fixed time gap between consecutive executions of a scheduled job.
Schedule Overlap
When a new job execution starts before the previous one has finished running.
Concurrency Policy
A rule that defines behavior when a new job run is triggered while a previous run is still active.
Execution Duration
The measured wall-clock time from when a job starts running to when it finishes.