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

ti-chi-bot commented 1 month 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。

codecov[bot] commented 1 month ago

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

:exclamation: No coverage uploaded for pull request base (release-8.1@d774c73). Click here to learn what that means.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## release-8.1 #53288 +/- ## ================================================ Coverage ? 71.1541% ================================================ Files ? 1465 Lines ? 421221 Branches ? 0 ================================================ Hits ? 299716 Misses ? 101029 Partials ? 20476 ``` | [Flag](https://app.codecov.io/gh/pingcap/tidb/pull/53288/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | Coverage Δ | | |---|---|---| | [unit](https://app.codecov.io/gh/pingcap/tidb/pull/53288/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `71.1541% <100.0000%> (?)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap#carryforward-flags-in-the-pull-request-comment) to find out more. | [Components](https://app.codecov.io/gh/pingcap/tidb/pull/53288/components?src=pr&el=components&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | Coverage Δ | | |---|---|---| | [dumpling](https://app.codecov.io/gh/pingcap/tidb/pull/53288/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `53.9957% <0.0000%> (?)` | | | [parser](https://app.codecov.io/gh/pingcap/tidb/pull/53288/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `∅ <0.0000%> (?)` | | | [br](https://app.codecov.io/gh/pingcap/tidb/pull/53288/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `40.9772% <0.0000%> (?)` | |

ti-chi-bot[bot] commented 1 month ago

[LGTM Timeline notifier]

Timeline:

2024-05-16 02:50:16.3369851 +0000 UTC m=+1707970.094120674: :ballot_box_with_check: agreed by hi-rustin.
2024-05-16 02:51:13.40417011 +0000 UTC m=+1708027.161305681: :ballot_box_with_check: agreed by tangenta.

tangenta commented 1 month ago

/approve

easonn7 commented 1 month ago

/approve

ti-chi-bot[bot] commented 1 month ago

[APPROVALNOTIFIER] This PR is APPROVED

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

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/pingcap/tidb/blob/release-8.1/OWNERS)~~ [hawkingrei,hi-rustin,tangenta] - ~~[pkg/parser/OWNERS](https://github.com/pingcap/tidb/blob/release-8.1/pkg/parser/OWNERS)~~ [easonn7,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