[Bug] There is a problem with the distribution strategy of the orca unionall operator.

[Light-City]

Cloudberry Database version

master

What happened

The orca optimizer currently returns the ANY policy for the first child of a unionall-like node, which will result in Gather Motion for the downstream chi
ldren and a 1:n Redistribution for the upstream.

for example:

    ->  Redistribute Motion 1:3  (slice2)
       ->  Append  (cost=0.00..863.91 rows=18001 width=12)
          ->  Finalize Vec Aggregate
            ->  Gather Motion 3:1  (slice3; segments: 3)
              ...
       ->  Gather Motion 3:1  (slice4; segments: 3)
          ->  HashAggregate

What you think should happen instead

remove child gather motion and upstream redis motion, just add 1:n to first child.

How to reproduce

tpcds 167 query

Operating System

centos7

Anything else

No response

Are you willing to submit PR?

• Yes, I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct.

[github-actions]

Hey, @Light-City welcome!🎊 Thanks for taking the time to point this out.🙌

[Light-City]

gpdb also fix this change, https://github.com/greenplum-db/gpdb/commit/0cd056a0a3d3c30a1d6d4479e67802b6673118c7