planner: support stable result mode (#25971)

[qw4990]

cherry-pick #25971 to release-5.0
You can switch your code base to this Pull Request by using git-extras:

# In tidb repo:
git pr https://github.com/pingcap/tidb/pull/25995

After apply modifications, you can push your change to this PR via:

git push [email protected]:ti-srebot/tidb.git pr/25995:release-5.1-c24a90f9e7f5

---

What problem does this PR solve?

Issue Number: close #xxx

Problem Summary: support stable result mode in the planner

What is changed and how it works?

Results of some queries are not stable, for example:

create table t (a int);
insert into t values (1), (2);
select a from t;

In the case above, the result can be 1 2 or 2 1, which is not stable.
This PR introduces a new switch that can make the results of these queries stable.

This feature is implemented as a logical optimization rule, which stabilizes results by modifying Sort in plans or inject new Sort into plans.
First, all operators are divided into 2 types:

1. input-order keepers: Selection, Projection, Limit;
2. all other operators.

The basic idea of this rule is:

1. iterate the plan from the root, and ignore all input-order keepers;
2. when meeting the first non-input-order keeper,
   2.1. if it's a Sort, complete it by appending its output columns into its order-by list,
   2.2. otherwise, inject a new Sort upon this operator.

Check List

Tests

• Unit test

Release note

• planner: support stable result mode

[qw4990]

/run-all-tests

[qw4990]

/run-all-tests

[qw4990]

/run-all-tests

[ti-chi-bot]

@time-and-fate: Thanks for your review. The bot only counts approvals from reviewers and higher roles in list, but you're still welcome to leave your comments.

In response to this:

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[time-and-fate]

/sig planner

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• Reminiscent
• time-and-fate

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

The full list of commands accepted by this bot can be found here.

Reviewer can indicate their review by submitting an approval review.
Reviewer can cancel approval by submitting a request changes review.

[Reminiscent]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 1926332

[qw4990]

/merge