planner: convert schema_name from NULL to "" for index advisor

[qw4990]

What problem does this PR solve?

Issue Number: ref #12303

Problem Summary: planner: convert schema_name from NULL to "" for index advisor

What changed and how does it work?

planner: convert schema_name from NULL to "" for index advisor

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

[tiprow]

Hi @qw4990. Thanks for your PR.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 56.3173%. Comparing base (3959803) to head (6dbe37b).
Report is 3 commits behind head on master.

Additional details and impacted files

@@                Coverage Diff                @@
##             master     #56943         +/-   ##
=================================================
- Coverage   73.3354%   56.3173%   -17.0182%     
=================================================
  Files          1638       1764        +126     
  Lines        453738     632640     +178902     
=================================================
+ Hits         332751     356286      +23535     
- Misses       100587     252299     +151712     
- Partials      20400      24055       +3655     

Flag	Coverage Δ
integration	37.0174% <0.0000%> (?)
unit	72.5529% <100.0000%> (-0.0007%)	⬇️

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

Components	Coverage Δ
dumpling	52.9478% <ø> (ø)
parser	∅ <ø> (∅)
br	52.6469% <ø> (+6.6480%)	⬆️

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hawkingrei, Rustin170506

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Needs approval from an approver in each of these files:

• OWNERS [Rustin170506,hawkingrei]
• pkg/planner/OWNERS [Rustin170506,hawkingrei]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-10-29 06:37:27.414587746 +0000 UTC m=+331760.253743289: ☑️ agreed by hawkingrei.
• 2024-10-29 07:07:08.610201013 +0000 UTC m=+333541.449356559: ☑️ agreed by Rustin170506.