Hmm So these functions were created from macros in commit 34694ec888d6, which themselves had been added for the first time in commit 37484ad2aace. However, it appears that they were added only because they were mirroring HeapTupleHeaderSetXminFrozen(), and while the latter was immediately used, the other two weren't and never have been.
(For a short while between June and September 2002 we had a different macro also called HeapTupleHeaderSetXminInvalid -- added by commit 3c35face4108 and removed by commit c7a165adc64e -- and curiously enough it was also entirely unused.) I think Andy is right that these should be removed, not only because they are unsafe but because they are dead code. codesearch.debian.net shows no matches by grep, other than htup_internals.h itself. -- Álvaro Herrera PostgreSQL Developer — https://www.EnterpriseDB.com/ "La rebeldía es la virtud original del hombre" (Arthur Schopenhauer)
