planner: increase tablescan cost for high risk scenarios | tidb-test=pr/2399

[terry1purcell]

What problem does this PR solve?

Issue Number: close #56012

Problem Summary:

What changed and how does it work?

Add a cost penalty to table scan if we encounter a scenario where a table scan may be risky or we should be preferencing away from table scan.

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 @terry1purcell. Thanks for your PR.

PRs from untrusted users cannot be marked as trusted with /ok-to-test in this repo meaning untrusted PR authors can never trigger tests themselves. Collaborators can still trigger tests on the PR using /test all.

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[terry1purcell]

/check-issue-triage-complete

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 75.3432%. Comparing base (448d569) to head (81b3d99).
Report is 1 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #56203        +/-   ##
================================================
+ Coverage   73.3954%   75.3432%   +1.9477%     
================================================
  Files          1624       1624                
  Lines        447375     447484       +109     
================================================
+ Hits         328353     337149      +8796     
+ Misses        98883      89806      -9077     
- Partials      20139      20529       +390     

Flag	Coverage Δ
integration	49.0787% <100.0000%> (?)
unit	72.4554% <100.0000%> (-0.0516%)	⬇️

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	52.2484% <ø> (+6.7190%)	⬆️

[terry1purcell]

/retest

[tiprow]

@terry1purcell: Cannot trigger testing until a trusted user reviews the PR and leaves an /ok-to-test message.

In response to this:

/retest

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 kubernetes-sigs/prow repository.

[terry1purcell]

/retest

[winoros]

/retest