planner: fix TPCDS Q64 regression under the new join algorithm (#69637)

[ti-chi-bot]

This is an automated cherry-pick of #69637

What problem does this PR solve?

Issue Number: ref #69600

Problem Summary: planner: fix TPCDS Q64 regression under the new CD-C join algorithm

What changed and how does it work?

In TPCDS Q64, ib1 and ib2 have the same row count, but the old join-order implementation is using SortStableFunc while the new one is using SortFunc, which leads to this join order change.

This PR update the new join-order implementation to also use SortStableFunc to keep the prior behavior.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No need to test

  • I checked and no code files have been changed.

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

Summary by CodeRabbit

• Tests
  • Added new TPC-DS test case coverage for a query plan scenario.
  • Included expected plan output to validate query behavior more reliably.

[ti-chi-bot]

This cherry pick PR is for a release branch and has not yet been approved by triage owners.
Adding the do-not-merge/cherry-pick-not-approved label.

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[APPROVALNOTIFIER] This PR is NOT APPROVED

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Details

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• pkg/planner/OWNERS

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 3ec99a03-b0f4-4451-810e-a77cb9cfefa2

📥 Commits

Reviewing files that changed from the base of the PR and between a13d3f6 and 41d1add.

📒 Files selected for processing (2)

• pkg/planner/core/casetest/tpcds/testdata/tpcds_suite_out.json
• pkg/planner/core/casetest/tpcds/testdata/tpcds_suite_xut.json

---

📝 Walkthrough

Walkthrough

This PR adds two new JSON test data files defining the TestTPCDSQ64 test case, each containing an explain format='plan_tree' SQL query and its expected physical plan tree output as a Result string array.

Changes

TPC-DS Q64 test suite data

Layer / File(s)	Summary
Add TestTPCDSQ64 test case data pkg/planner/core/casetest/tpcds/testdata/tpcds_suite_out.json, pkg/planner/core/casetest/tpcds/testdata/tpcds_suite_xut.json	New JSON test suite files defining the TestTPCDSQ64 case with the SQL query and expected plan-tree Result output.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related issues

• planner: TPCDS Q64 plan regression caused by new cd-c join algorithm #69600: Adds TPC-DS Q64 plan-tree test cases, directly matching the Q64 planner regression referenced in this issue.

Suggested reviewers: qw4990, hawkingrei, AilinKid

Poem

A rabbit hops through JSON trees,
Q64's plan laid out with ease,
Cases added, results in line,
TPC-DS tests now shine,
Thump-thump, all tests agree! 🐰

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly matches the main change: fixing the TPCDS Q64 regression in the planner.
Description check	✅ Passed	The description follows the template with issue reference, problem summary, change details, tests, and release note block.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (release-8.5@a13d3f6). Learn more about missing BASE report.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-8.5     #69654   +/-   ##
================================================
  Coverage               ?   55.1238%           
================================================
  Files                  ?       1849           
  Lines                  ?     666253           
  Branches               ?          0           
================================================
  Hits                   ?     367264           
  Misses                 ?     271613           
  Partials               ?      27376           

Flag	Coverage Δ
integration	38.2052% <ø> (?)
unit	65.1691% <ø> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	55.3108% <0.0000%> (?)
parser	∅ <0.0000%> (?)
br	54.8112% <0.0000%> (?)

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