Re: Using each rel as both outer and inner for JOIN_ANTI

Richard Guo <guofenglinux(at)gmail(dot)com> writes:
> Thanks for reminding. Attached is the rebased patch, with no other
> changes. I think the patch is ready for commit.

Pushed after a little further fooling with the comments. I also had
to rebase it over 11c2d6fdf (Parallel Hash Full Join). I think I did
that correctly, but it's not clear to me whether any of the existing
test cases are now doing parallelized hashed right antijoins. Might
be worth a little more testing.

I think that Alvaro's concern about incorrect cost estimates may be
misplaced. I couldn't find any obvious errors in the costing logic for
this, given that we concluded that the early-exit runtime logic cannot
apply. Also, when I try simply executing Richard's original test query
(in a non-JIT build), the runtimes I get line up quite well ... maybe
too well? ... with the cost estimates:

v15 HEAD w/patch Ratio

Cost estimate 173691.19 90875.33 0.52
Actual (best of 3) 514.200 ms 268.978 ms 0.52

I think the smaller differentials you guys were seeing were all about
EXPLAIN ANALYZE overhead.

regards, tom lane