https://nalar.dev/tags/checkpoints/ Recent content in Checkpoints on Nalar Hugo en-us Tue, 15 Sep 2026 00:00:00 +0700 https://nalar.dev/postgresql-full-page-writes-repair-torn-pages/ Tue, 15 Sep 2026 00:00:00 +0700 https://nalar.dev/postgresql-full-page-writes-repair-torn-pages/ <p>A PostgreSQL data page can be larger than the atomic write unit provided by storage. If the host fails while a page is being written, part of that page may reach durable storage while another part remains from an older version. Recovery cannot safely apply ordinary change records to a page whose internal structure may already be inconsistent.</p> <p><code>full_page_writes</code> addresses that failure mode. With the setting enabled, PostgreSQL records a complete image of a page in write-ahead log (WAL) on the first modification of that page after a checkpoint. During crash recovery, that image can replace a torn on-disk page before later WAL records are replayed.</p> https://nalar.dev/postgresql-full-page-writes-raise-wal-volume-after-checkpoints/ Tue, 15 Sep 2026 00:00:00 +0700 https://nalar.dev/postgresql-full-page-writes-raise-wal-volume-after-checkpoints/ <p>A PostgreSQL page modified for the first time after a checkpoint can generate much more WAL than a later modification to the same page. With <code>full_page_writes</code> enabled, the first protected change records a full page image so crash recovery can reconstruct a page even if an operating-system failure interrupts a physical page write.</p> <p>That protection creates a recurring WAL pattern tied to checkpoint boundaries. A checkpoint resets the condition for pages, and subsequent writes gradually encounter pages that need a new full page image.</p>