planner: fix unique key get wrong row count when to query the NULL value | tidb-test=pr/2390

[hawkingrei]

What problem does this PR solve?

Issue Number: close #56116

Problem Summary:

What changed and how does it work?

There will be issues with the row count under index/unique index. Previously, we would uniformly count the row count for this PointGet as 1, but if it is null, it will no longer be 1 and must be calculated according to the null count.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

From internal test cases

• 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

[hawkingrei]

/check-issue-triage-complete

[hawkingrei]

/check-issue-triage-complete

[hawkingrei]

/retest

[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 4 lines in your changes missing coverage. Please review.

Project coverage is 56.1193%. Comparing base (3ae6470) to head (39b3939).
Report is 20 commits behind head on master.

Additional details and impacted files

@@                Coverage Diff                @@
##             master     #56117         +/-   ##
=================================================
- Coverage   72.8947%   56.1193%   -16.7755%     
=================================================
  Files          1611       1737        +126     
  Lines        447371     626622     +179251     
=================================================
+ Hits         326110     351656      +25546     
- Misses       101188     251234     +150046     
- Partials      20073      23732       +3659     

Flag	Coverage Δ
integration	37.2033% <75.0000%> (?)
unit	72.1074% <75.0000%> (+0.1038%)	⬆️

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

Components	Coverage Δ
dumpling	52.9567% <ø> (ø)
parser	∅ <ø> (∅)
br	52.9089% <ø> (+7.1102%)	⬆️

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: qw4990, winoros

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

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [qw4990,winoros]
• pkg/planner/OWNERS [qw4990,winoros]

Approvers can indicate their approval by writing /approve in a comment
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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-09-18 12:40:49.32635224 +0000 UTC m=+1051319.066776179: ☑️ agreed by winoros.
• 2024-09-19 03:27:21.775939883 +0000 UTC m=+1104511.516363823: ☑️ agreed by qw4990.

[hawkingrei]

/cherrypick release-8.1

[ti-chi-bot]

@hawkingrei: new pull request created to branch release-8.1: #56154.

In response to this:

/cherrypick release-8.1

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.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.5: #56191.

[hawkingrei]

/cherrypick release-7.5

[ti-chi-bot]

@hawkingrei: new pull request could not be created: failed to create pull request against pingcap/tidb#release-7.5 from head ti-chi-bot:cherry-pick-56117-to-release-7.5: status code 422 not one of [201], body: {"message":"Validation Failed","errors":[{"resource":"PullRequest","code":"custom","message":"A pull request already exists for ti-chi-bot:cherry-pick-56117-to-release-7.5."}],"documentation_url":"https://docs.github.com/rest/pulls/pulls#create-a-pull-request","status":"422"}

In response to this:

/cherrypick release-7.5

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.

[hawkingrei]

/cherrypick release-6.5

[ti-chi-bot]

@hawkingrei: new pull request created to branch release-6.5: #56277.

In response to this:

/cherrypick release-6.5

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.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #56331.