# An overnight ETL produced four kinds of errors last week: HTTP 503 from a downstream during a CPU sp

Canonical URL: <https://datadriven.io/problems/an-overnight-etl-produced-four-kinds-of-errors-last-week-ht-d26eeaed>

Domain: Pipeline Design · Difficulty: medium

## Problem

An overnight ETL produced four kinds of errors last week: HTTP 503 from a downstream during a CPU spike, HTTP 401 because a service-account token expired, HTTP 429 from a rate limiter that returned a Retry-After header, and a JSON parse error on one malformed row out of two million. The section names two buckets (transient, permanent) plus a third pragmatic case (ambiguous). Classify the failure: add four classifier marker nodes downstream of the ingest transform, one per error, whose names state which bucket the error belongs to and the response that follows.

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