This patch, which is built upon the "HeapTupleHeader accessor macros"

This patch, which is built upon the "HeapTupleHeader accessor macros"
patch from 2002-06-10, is supposed to reduce the heap tuple header size
by four bytes on most architectures.  Of course it changes the on-disk
tuple format and therefore requires initdb.

This overlays cmin/cmax/xmax fields into only two fields.

Manfred Koizar