By Ether DataRequest data sample
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Distributed systemsCase 01 of 05

Duplicate event replay

At-least-once delivery replays the same event, with an identical event timestamp but a new ingestion time. Naive counting double-counts the slot.

Class
Case to account for
Affects
2 conversions
01

Detection

Repeated (idempotency key, event time) with differing ingestion times.

02

Mitigation

01
Deduplicate by idempotency key + event time before aggregating into a slot.
03

Affected conversions

Timestamp + zonehour-of-week slot
OPEN
semantics
OPEN