hot-standby-feedback · shipping · also PostgreSQL hot_standby_feedback

Hot standby feedback

Hot standby feedback is PostgreSQL's mechanism for reporting standby query retention needs upstream to defer conflicting row cleanup.

Related Observatory article: Hot standby feedback on hesela.com

It can prevent cleanup-related query cancellations but retain dead rows and cause primary-side bloat; the default is off. [1] It does not configure commit acknowledgements. [4]

Relations

related

replication-slot, failover-slot, logical-decoding, snapshot-isolation

Limitations

• Feedback does not eliminate every recovery conflict, including Access Exclusive locks and drops of tables, databases or tablespaces. [2]
• Slot synchronization needs a persistent physical upstream slot, which can be the existing streaming slot; feedback alone does not protect needed catalog history during a disconnection. [3]

Citations

1. PostgreSQL 18: hot_standby_feedback (accessed 2026-10-16)
2. PostgreSQL 18: handling query conflicts on hot standby (accessed 2026-10-16)
3. PostgreSQL 18: replication slot synchronization (accessed 2026-10-16)
4. Hesela: Replication acknowledgements and logical failover readiness (accessed 2026-10-16)

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