Suresh <suiyengar(at)yahoo(dot)com> writes:
> What is the time qualification check ?
HeapTupleSatisfiesVisibility(). See
src/include/utils/tqual.h
src/backend/utils/time/tqual.c
and if none of this is making any sense maybe you need to start here:
http://developer.postgresql.org/pgdocs/postgres/mvcc.html
regards, tom lane