until such time as a tuple is inserted, updated, deleted, or locked on

that page. The page-level <literal>PD_ALL_VISIBLE</literal> bit has the

same meaning as the all-visible bit in the visibility map, but is stored

within the data page itself rather than a separate datatructure. These

within the data page itself rather than a separate datastructure. These

will normally agree, but the page-level bit can sometimes be set while the

visibility map bit is clear after a crash recovery; or they can disagree

because of a change which occurs after <literal>pg_visibility</> examines