ng-galien opened a new pull request, #1117: URL: https://github.com/apache/pulsar-site/pull/1117
### ✅ Contribution Checklist - [x] I read the [contribution guide](https://pulsar.apache.org/contribute/document-contribution/) - [x] I updated the [versioned docs](https://pulsar.apache.org/contribute/document-contribution/#update-versioned-docs) ## Summary Add caution admonitions to warn users that `DeadLetterPolicy.maxRedeliverCount` is silently unreliable when `negativeAcknowledge` is used as the retry mechanism. The redelivery counter is kept only in memory (client-side and broker-side). It resets to zero on broker restart, bundle unload/rebalance, topic unload, or consumer disconnect. In practice, failing messages can be redelivered indefinitely and the dead letter topic may never be reached. Three sections updated in `concepts-messaging.md`: 1. **Negative acknowledgment** — new `:::caution` block explaining the issue and recommending `reconsumeLater` with `enableRetry(true)` 2. **Retry letter topic** — expanded existing note to clarify that retry letter topic is the only mechanism that guarantees `maxRedeliverCount` is honored 3. **Dead letter topic** — new `:::caution` block warning that `maxRedeliverCount` may not be honored without `enableRetry(true)` Changes propagated to versioned docs (3.0.x, 4.0.x, 4.2.x) via `docs-tool.sh`. Verified with a self-contained reproduction across Pulsar 2.11.0, 3.3.9, and 4.2.0 (broker and client): https://github.com/ng-galien/bug-pulsar Closes apache/pulsar#25533 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
