planner: make `var_samp` can be used as a window function (#53130)

ti-chi-bot commented 2 weeks ago

This is an automated cherry-pick of #53130

What problem does this PR solve?

Issue Number: close https://github.com/pingcap/tidb/issues/52933

Problem Summary:

What changed and how does it work?

From the MySQL plan:

mysql> explain analyze select var_samp(c1) over (partition by c1) from t1;
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| EXPLAIN                                                                                                                                                                                                                                                                                                                |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| -> Window aggregate with buffering: var_samp(t1.c1) OVER (PARTITION BY t1.c1 )   (cost=0 rows=1) (actual time=0.139..0.139 rows=0 loops=1)
    -> Sort: t1.c1  (cost=0.35 rows=1) (actual time=0.133..0.133 rows=0 loops=1)
        -> Table scan on t1  (cost=0.35 rows=1) (actual time=0.116..0.116 rows=0 loops=1)
 |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)

Made var_samp can be used as a window function.
Added a test case for https://github.com/pingcap/tidb/issues/52933.

Check List

Tests

[x] Unit test
[ ] Integration test
[x] 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.

Make `var_samp` can be used as a window function.
使 `var_samp` 可以用作窗口函数。

ti-chi-bot[bot] commented 2 weeks ago

@ti-chi-bot: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
idc-jenkins-ci-tidb/build	a0ee23f9509147ca357bfaa5f256201f18fad2b4	link	true	`/test build`
idc-jenkins-ci-tidb/unit-test	a0ee23f9509147ca357bfaa5f256201f18fad2b4	link	true	`/test unit-test`
idc-jenkins-ci-tidb/check_dev	a0ee23f9509147ca357bfaa5f256201f18fad2b4	link	true	`/test check-dev`

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ti-chi-bot[bot] commented 2 weeks ago

[LGTM Timeline notifier]

Timeline:

2024-05-16 02:52:20.383773615 +0000 UTC m=+1708094.140909173: :ballot_box_with_check: agreed by tangenta.

easonn7 commented 2 weeks ago

/approve

ti-chi-bot[bot] commented 2 weeks ago

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: easonn7, tangenta

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/pingcap/tidb/blob/release-7.1/OWNERS)~~ [tangenta] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

pingcap / tidb