What is Fixed Delay?
A scheduling mode that waits a fixed time after the previous execution finishes before starting the next.
Definition
Fixed delay scheduling starts the countdown for the next execution only after the current execution completes. If a job is configured with a 5-minute fixed delay and takes 2 minutes to run, the next execution starts 7 minutes after the previous one began (2 minutes running + 5 minutes waiting). This guarantees a minimum gap between executions but means the actual interval varies based on execution duration.
Simple Analogy
Like taking a 15-minute break between meetings — no matter how long the meeting runs, you always get your 15-minute breather afterward before the next one starts.
Why It Matters
Fixed delay prevents job overlap by design. If your job processes a queue or calls an external API, fixed delay ensures each execution fully completes before the next one begins. This is critical for jobs that cannot safely run concurrently — database migrations, sequential data processing, or resource-intensive batch operations.
How to Verify
Compare your job start times. If the gap between the end of one execution and the start of the next is consistent, you have fixed delay scheduling. If the gap between start times is consistent regardless of execution duration, you have fixed rate scheduling instead.
Common Mistakes
Confusing fixed delay with fixed rate — fixed rate keeps the interval between start times constant, while fixed delay keeps the gap after completion constant. Not accounting for execution time when calculating throughput. Expecting exact periodicity when execution durations vary.
Best Practices
Use fixed delay when job overlap would cause problems — data corruption, duplicate processing, or resource exhaustion. For jobs that must maintain exact periodicity regardless of execution time, use fixed rate instead. In CronJobPro, configure overlap prevention to achieve fixed-delay behavior with cron-based scheduling.
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Try it free →Frequently Asked Questions
What is Fixed Delay?
Fixed delay scheduling starts the countdown for the next execution only after the current execution completes. If a job is configured with a 5-minute fixed delay and takes 2 minutes to run, the next execution starts 7 minutes after the previous one began (2 minutes running + 5 minutes waiting). This guarantees a minimum gap between executions but means the actual interval varies based on execution duration.
Why does Fixed Delay matter for cron jobs?
Fixed delay prevents job overlap by design. If your job processes a queue or calls an external API, fixed delay ensures each execution fully completes before the next one begins. This is critical for jobs that cannot safely run concurrently — database migrations, sequential data processing, or resource-intensive batch operations.
What are best practices for Fixed Delay?
Use fixed delay when job overlap would cause problems — data corruption, duplicate processing, or resource exhaustion. For jobs that must maintain exact periodicity regardless of execution time, use fixed rate instead. In CronJobPro, configure overlap prevention to achieve fixed-delay behavior with cron-based scheduling.
Related Terms
Fixed Rate
A scheduling mode that runs jobs at exact intervals regardless of how long each execution takes.
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.