planner: improve range underestimation

[terry1purcell]

What problem does this PR solve?

Issue Number: close #53907

Problem Summary:

What changed and how does it work?

Range predicate estimation is changed to default to a minimum of 1/NDV for each of the low & high values (thus 2/NDV) which is consistent with the estimation used for 2 point-get values.

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

[ti-chi-bot]

Hi @terry1purcell. Thanks for your PR.

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[tiprow]

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[hawkingrei]

/ok-to-test

[terry1purcell]

/retest

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 55.9339%. Comparing base (6ba9435) to head (bfca395).

Additional details and impacted files

@@                Coverage Diff                @@
##             master     #53860         +/-   ##
=================================================
- Coverage   72.6829%   55.9339%   -16.7491%     
=================================================
  Files          1515       1637        +122     
  Lines        434590     606551     +171961     
=================================================
+ Hits         315873     339268      +23395     
- Misses        99395     243951     +144556     
- Partials      19322      23332       +4010     

Flag	Coverage Δ
integration	37.0545% <100.0000%> (?)
unit	71.4998% <100.0000%> (-0.1800%)	⬇️

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

Components	Coverage Δ
dumpling	52.9656% <ø> (ø)
parser	∅ <ø> (∅)
br	50.6095% <ø> (+8.3637%)	⬆️

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-06-13 15:10:05.122697156 +0000 UTC m=+650159.176009077: ☑️ agreed by winoros.

[qw4990]

/retest

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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