Re: BUG #17618: unnecessary filter column <> text even after adding index

Richard Guo <guofenglinux@gmail.com> writes:
> I've updated the patch according to the suggestions as in v4.  Thanks
> for reviewing this patch!

I was about ready to commit this when I re-read your initial comment
and realized that there's a second way to fix it.  We can improve
predtest.c so that it understands that "x = true" implies "x" and
so on, whereupon the existing logic in create_bitmap_scan_plan
handles the case correctly.  This is pretty nearly the same code as
in your v4, except that it's in a considerably less hot code path, plus
there's at least some chance that it could be useful for other purposes.
So I think I like this way better.  Thoughts?