Semicolony ELI5 · comic

Exponential backoff.

Retry the way you re-text a silent friend: once soon, then with longer and longer gaps.

  1. Hello? Still me.
    knock knock no answer
    1

    Most failures are weather, not climate: a restart, a blip, a dropped packet. Weather deserves a retry.

  2. wait 1s, then retry
    2

    The first pause is tiny on purpose — a glitch that lasts milliseconds should cost about that much.

  3. 1s 2s 4s 8s ×2
    3

    Doubling stretches ten failures into minutes of waiting without anyone having to tune a schedule.

  4. struggling a retry storm keeps it down
    4

    Instant retries are how a service’s own clients keep it on the floor after the original problem has passed.

  5. jitter scatters them
    5

    Clients that failed in the same instant would retry in the same instant — the randomness breaks up the wave.

  6. cap cap the wait, then give up
    6

    Patience needs an exit: cap the pause, budget the attempts, and report failure while the report still helps.

Knock again, but wait longer each time, with a random spread and a limit.
Semicolony semicolony.dev/eli5/exponential-backoff/comic
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