Re: hash-join forgets tuples

Sebastian Freundt <hroptatyr@gna.org> writes:
> using a highly surjective left (or inner) join to a table reveals data
> loss if the hash join method is used.

In which PG version?  Given that you appear to be playing with 8.1devel
code, you might be needing this bug fix:

2005-07-23 22:25  tgl

    * src/backend/nodes/tidbitmap.c: Fix logic error in tbm_intersect:
    the intersection of a normal page and a lossy page has to be lossy,
    because we don't know exactly which tuples on the page should
    remain part of the bitmap.  Per Jie Zhang.

If not, please send along a self-contained test case.

            regards, tom lane