https://nalar.dev/tags/toast/ Recent content in TOAST on Nalar Hugo en-us Tue, 15 Sep 2026 00:00:00 +0700 https://nalar.dev/postgresql-toast-moves-large-values-outside-heap-rows/ Tue, 15 Sep 2026 00:00:00 +0700 https://nalar.dev/postgresql-toast-moves-large-values-outside-heap-rows/ <h1 id="postgresql-toast-moves-large-values-outside-heap-rows">PostgreSQL TOAST Moves Large Values Outside Heap Rows</h1> <p>PostgreSQL heap tuples cannot span data pages. A row containing a large <code>text</code>, <code>bytea</code>, <code>jsonb</code>, or other variable-length value therefore cannot simply continue onto the next heap page. TOAST provides the storage mechanism that keeps such rows representable: eligible values can be compressed, moved out of line, or both.</p> <p>The visible SQL value does not change when this happens. The physical representation does. A heap tuple may contain a compact reference while the value&rsquo;s bytes reside as chunk rows in a separate relation associated with the table.</p>