Re: Oversight in reparameterize_path_by_child leading to executor crash

Hi Tom,

On Tue, Aug 22, 2023 at 2:18 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:

>
> (BTW, I did look at Ashutosh's idea of merging the
> reparameterize_path_by_child and path_is_reparameterizable_by_child
> functions, but I didn't think that would be an improvement,
> because we'd have to clutter reparameterize_path_by_child with
> a lot of should-I-skip-this-step tests.  Some of that could be
> hidden in the macros, but a lot would not be.  Another issue
> is that I do not think we can change reparameterize_path_by_child's
> API contract in the back branches, because we advertise it as
> something that FDWs and custom scan providers can use.)

Here are two patches
0001 same as your v5 patch
0002 implements what I had in mind - combining the assessment and
reparameterization in a single function.

I don't know whether you had something similar to 0002 when you
considered that approach. Hence implemented it quickly. The names of
the functions and arguments can be changed. But I think this version
will help us keep assessment and actual reparameterization in sync,
very tightly. Most of the conditionals have been pushed into macros,
except for two which need to be outside the macros and actually look
better to me. Let me know what you think of this.

FWIW I ran make check and all the tests pass.

I agree that we can not consider this for backbranches but we are
anyway thinking of disabling reparameterization for tablesample scans
anyway.

--
Best Wishes,
Ashutosh Bapat