{
  "slug": "hot-standby-feedback",
  "term": "Hot standby feedback",
  "aliases": [
    "PostgreSQL hot_standby_feedback"
  ],
  "definition": "Hot standby feedback is PostgreSQL's mechanism for reporting standby query retention needs upstream to defer conflicting row cleanup.",
  "note": "It can prevent cleanup-related query cancellations but retain dead rows and cause primary-side bloat; the default is off. [pg-feedback] It does not configure commit acknowledgements. [hesela-replication]",
  "status": "shipping",
  "advantages": [],
  "limitations": [
    {
      "text": "Feedback does not eliminate every recovery conflict, including Access Exclusive locks and drops of tables, databases or tablespaces.",
      "citationIds": [
        "pg-conflicts"
      ]
    },
    {
      "text": "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.",
      "citationIds": [
        "pg-decoding"
      ]
    }
  ],
  "related": [
    "replication-slot",
    "failover-slot",
    "logical-decoding",
    "snapshot-isolation"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-16",
  "citations": [
    {
      "id": "pg-feedback",
      "title": "PostgreSQL 18: hot_standby_feedback",
      "url": "https://www.postgresql.org/docs/18/runtime-config-replication.html#GUC-HOT-STANDBY-FEEDBACK",
      "accessed": "2026-10-16"
    },
    {
      "id": "pg-conflicts",
      "title": "PostgreSQL 18: handling query conflicts on hot standby",
      "url": "https://www.postgresql.org/docs/18/hot-standby.html#HOT-STANDBY-CONFLICT",
      "accessed": "2026-10-16"
    },
    {
      "id": "pg-decoding",
      "title": "PostgreSQL 18: replication slot synchronization",
      "url": "https://www.postgresql.org/docs/18/logicaldecoding-explanation.html#LOGICALDECODING-REPLICATION-SLOTS-SYNCHRONIZATION",
      "accessed": "2026-10-16"
    },
    {
      "id": "hesela-replication",
      "title": "Hesela: Replication acknowledgements and logical failover readiness",
      "url": "https://hesela.com/analyses/replication-acknowledgements-durability-lag/",
      "accessed": "2026-10-16"
    }
  ]
}