Re: Re: fix cost subqueryscan wrong parallel cost

On Thu, Apr 21, 2022 at 2:38 AM bucoo@sohu.com <bucoo@sohu.com> wrote:
> > Suppose parallelism is not in use and that param_info is NULL. Then,
> > is path->subpath->rows guaranteed to be equal to baserel->rows? If
> > yes, then we don't need to a three-part if statement as you propose
> > here and can just change the "else" clause to say path->path.rows =
> > path->subpath->rows. If no, then your change gives the wrong answer.
>
> I checked some regress test, Sometimes subquery scan have filter,
> so path->subpath->row guaranteed *not* to be equal to baserel->rows.
> If the first patch is false, I don't known how to fix this,
> looks like need someone's help.

Please fix your mailer so that it doesn't send me a bounce message
every time I reply to one of your messages on list.

I don't know how to fix this right now either, then; maybe I or
someone else will have a good idea later.

-- 
Robert Haas
EDB: http://www.enterprisedb.com