{
  "slug": "page-differential-logging",
  "term": "Page-differential logging",
  "aliases": [
    "PDL"
  ],
  "definition": "Page-differential logging stores a logical page as a retained base and its current difference, computed when the page is written back.",
  "note": "Multiple differentials share a physical page. With equal logical and physical page sizes, reconstruction reads at most two physical pages; an oversized differential becomes a new full base. The comparison requires reading the old base. [pdl2010]\n\nRecovery assumes atomic page programming and loses unflushed buffered differences. The evaluation uses an emulator, not a contemporary SSD benchmark. [pdl2010]",
  "status": "research",
  "advantages": [],
  "limitations": [],
  "related": [
    "ftl",
    "write-amplification",
    "nand-page",
    "cache-flush",
    "in-page-logging"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "pdl2010",
      "title": "Kim, Whang and Song. Page-Differential Logging. SIGMOD 2010, pp. 363-374, sections 4.1-4.5 and 5.1.",
      "url": "https://dblab.kaist.ac.kr/Prof/pdf/Kim2010.pdf",
      "accessed": "2026-11-13"
    },
    {
      "id": "hesela-pdl",
      "title": "Hesela: page differences and physical write accounting",
      "url": "https://hesela.com/analyses/nand-erase-block-size-gc-cost/#page-differential-logging",
      "accessed": "2026-11-13"
    }
  ],
  "updated": "2026-11-13",
  "provenance": [
    "Historical source synthesis. No prototype execution, hardware measurement or benchmark reproduction by Hesela."
  ]
}