{
  "slug": "incremental-backup",
  "term": "Incremental backup",
  "aliases": [],
  "definition": "An incremental backup represents changes relative to an earlier backup and requires that reference and any further dependencies to reconstruct omitted data.",
  "note": "The reference need not be the immediately previous backup. Recovery requires the retained dependency set, not only the newest increment. PostgreSQL physical incremental backups also need recovery WAL; combining their files is not log replay.",
  "status": "shipping",
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-13",
  "advantages": [
    {
      "text": "Can reduce copied data when much of a large database is unchanged.",
      "citationIds": [
        "archive"
      ]
    }
  ],
  "limitations": [
    {
      "text": "A missing required predecessor can prevent reconstruction.",
      "citationIds": [
        "combine"
      ]
    },
    {
      "text": "A legal dependency chain does not establish input integrity.",
      "citationIds": [
        "combine"
      ]
    }
  ],
  "related": [
    "backup-manifest",
    "backup-verification",
    "restore-test",
    "snapshot"
  ],
  "citations": [
    {
      "id": "combine",
      "title": "PostgreSQL 18: pg_combinebackup, dependency chains and hard links",
      "url": "https://www.postgresql.org/docs/18/app-pgcombinebackup.html",
      "accessed": "2026-10-13"
    },
    {
      "id": "archive",
      "title": "PostgreSQL 18: Continuous Archiving and Point-in-Time Recovery, sections 25.3.3 and 25.3.5",
      "url": "https://www.postgresql.org/docs/18/continuous-archiving.html",
      "accessed": "2026-10-13"
    },
    {
      "id": "hesela-backup-evidence",
      "title": "Hesela: Backup verification is not a restore test",
      "url": "https://hesela.com/analyses/backup-verification-is-not-a-restore-test/",
      "accessed": "2026-10-13"
    }
  ]
}