Dead-letter queues and replay

Bad Kafka payloads are quarantined into analytics.parse_errors so valid rows in the same batch still normalize. Source-specific DLQs and normalization.errors capture accountability.

flowchart TD M[Malformed message] PE[parse_errors] DLQ[Source DLQ topic] NE[normalization.errors] M --> PE M --> DLQ M --> NE OP[Operator replay] PE --> OP DLQ --> OP

Replay tooling

• make replay-bad-fixtures — publishes intentionally bad payloads for testing.
• scripts/replay_dlq.sh — DRY_RUN=1 by default; explicit flags for resolving rows.

Bookkeeping

analytics.dlq_replay_runs / analytics.dlq_replay_items record replay attempts when enabled.

Compaction

make parse-errors-compact defaults to report-only (DRY_RUN=1) — avoid deleting accountability rows without an explicit archival policy.