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

On Tue, Nov 8, 2022 at 5:06 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:

> 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?


It works for me.  predtest.c is a more common place so that there may be
other cases that can benefit from this change.  Thanks for the new
patch!

Thanks
Richard