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Semicolony ELI5 · comic

Exponential backoff.

When a call fails, wait a little, then twice as long, then twice again — instead of hammering away.

  1. knock knock no answer
    1

    You knock on a door and nobody answers — the call to another service just failed.

  2. wait 1s, then retry
    2

    So you wait a short moment, then try again — a quick first retry handles a blip.

  3. 1s 2s 4s 8s ×2
    3

    Still failing? Each wait doubles: 1s, 2s, 4s, 8s — backing off further every time.

  4. struggling a retry storm keeps it down
    4

    This matters because everyone retrying instantly is a stampede that keeps the service down.

  5. jitter scatters them
    5

    Adding jitter, a little randomness, scatters the retries so they do not arrive in sync.

  6. cap cap the wait, then give up
    6

    Finally, cap how long you wait and stop after a limit, so you never retry forever.

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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