What's the purpose of mark/restrpos in heapam.c?
AFAIK, mark/restore is only used by merge joins, and you can't feed a
merge join from a heap scan because merge join requires sorted input.
Unless I'm missing something, heap_markpos and heap_restrpos are dead code.
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com