First in First Out

Intro

First in first out (FIFO) means items are used or processed in the order they arrive. It matters because FIFO reduces aging inventory and ensures predictable flow.

Key points:

• Upstream process fills a queue; downstream consumes in arrival order.
• Stops production when the FIFO lane is full to prevent overproduction.
• Common use cases: work queues (BPM), message queues (Tech), batch jobs (Apps), inventory lanes.
• Pitfall: ignoring FIFO capacity, causing bottlenecks or idle time.

Examples:

• Support tickets processed strictly by arrival time.
• Message broker delivering tasks to workers in FIFO order.
• Manufacturing cells using FIFO lanes to balance flow.

In practice:

Set clear FIFO capacities and monitor queue metrics to trigger upstream adjustments.

Related terms: queue; lean; throughput

FAQs:

Q: Is FIFO always optimal?
A: No; use priority or SLAs where critical requests must jump the queue.

Q: How is FIFO enforced in systems?
A: With queue data structures and ordered consumption logic.

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