Re: Some dead code in get_param_path_clause_serials() - Mailing list pgsql-hackers

On Wed, Nov 13, 2024 at 9:59 PM Andrei Lepikhov <lepihov@gmail.com> wrote:
> On 11/13/24 16:34, Richard Guo wrote:
> > The function get_param_path_clause_serials() is used to get the set of
> > pushed-down clauses enforced within a parameterized Path.  Since we
> > don't currently support parameterized MergeAppend paths, and it
> > doesn't look like that is going to change anytime soon (as explained
> > in the comments for generate_orderedappend_paths), we don't need to
> > consider MergeAppendPath in this function.  Is it worth removing the
> > related code, as attached?
> >
> > This change won't make any measurable difference in performance; it's
> > just for clarity's sake.

> I've passed through the logic of
> get_param_path_clause_serials/reparameterize_path_by_child/reparameterize_path.
> Agree, it seems not useful to parameterise ordered appends in the near
> future.

Thanks for the review.

> Even So, it would be better to insert changes, induced by new
> feature by one commit.

I'm not sure I understand what you mean by this sentence.

> By the way, Do you know if anyone gave a speech on the current state of
> internal plan parameterisation and its possible development directions?
> It would be helpful to have such an explanation.

Not that I'm aware of, but I found the "Parameterized Paths" section
in optimizer/README to be very helpful.

Thanks
Richard