docs: proposal of checkpoint for backup

[Leavrth]

What problem does this PR solve?

Issue Number: ref #38647

Problem Summary:

What is changed and how it works?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

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]

[REVIEW NOTIFICATION]

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• 3pointer

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[Leavrth]

/run-integration-br-test

[Leavrth]

/run-integration-br-test

[Leavrth]

/run-integration-br-test

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.6767%. Comparing base (63ce793) to head (2e29b54).
Report is 5961 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #39568        +/-   ##
================================================
+ Coverage   73.4304%   79.6767%   +6.2462%     
================================================
  Files          1066       3600      +2534     
  Lines        339121    1049476    +710355     
================================================
+ Hits         249018     836188    +587170     
- Misses        74083     174226    +100143     
- Partials      16020      39062     +23042