ddl: enhance row size estimation before adding index

[tangenta]

What problem does this PR solve?

Issue Number: close #52085

Problem Summary: See #52085.

What changed and how does it work?

• Move avarage row size estimation to the beginning of adding index.
• Use approximate-key-size * MB / approximate-keys from region info fetched by PD client to enhance row size estimation.

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 @tangenta. Thanks for your PR.

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[codecov]

Codecov Report

Merging #52086 (0ac1463) into master (75c8347) will decrease coverage by 16.0419%.
Report is 10 commits behind head on master.
The diff coverage is 67.8899%.

Additional details and impacted files

@@                Coverage Diff                @@
##             master     #52086         +/-   ##
=================================================
- Coverage   70.6807%   54.6389%   -16.0419%     
=================================================
  Files          1486       1597        +111     
  Lines        439452     610629     +171177     
=================================================
+ Hits         310608     333641      +23033     
- Misses       109337     253743     +144406     
- Partials      19507      23245       +3738     

Flag	Coverage Δ
integration	36.6812% <65.1376%> (?)
unit	70.4238% <32.1100%> (-0.0680%)	⬇️

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

Components	Coverage Δ
dumpling	53.9957% <ø> (ø)
parser	∅ <ø> (∅)
br	50.9560% <ø> (+5.1373%)	⬆️

[ywqzzy]

statsCache only updated when we access infoschema.Table/Columns, maybe read stats from mysql.stats_meta and mysql.stats_histograms;

[tangenta]

Updated.

[ywqzzy]

Rest LGTM

[tangenta]

/hold

[tangenta]

/unhold

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ywqzzy, zimulala

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Needs approval from an approver in each of these files:

• OWNERS [ywqzzy,zimulala]
• pkg/ddl/OWNERS [ywqzzy,zimulala]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-03-26 03:25:55.011139614 +0000 UTC m=+1951982.033386002: ☑️ agreed by ywqzzy.
• 2024-03-27 02:24:46.692264103 +0000 UTC m=+2034713.714510491: ☑️ agreed by zimulala.