statistics: use []float64 to represent hot peer loads

[lhy1024]

What problem does this PR solve?

Currently, all hot peer loads are saved in different variables and accessed using different functions.
Too many duplicated code and hard to extend.

What is changed and how it works?

Save loads using []float64 and access them using enums.

Check List

Tests

• Unit test

Release note

• No release note

[codecov]

Codecov Report

Merging #3591 (9e5f8b9) into master (b07be86) will increase coverage by 0.17%.
The diff coverage is 85.59%.

@@            Coverage Diff             @@
##           master    #3591      +/-   ##
==========================================
+ Coverage   74.52%   74.70%   +0.17%     
==========================================
  Files         245      245              
  Lines       24155    24195      +40     
==========================================
+ Hits        18002    18075      +73     
+ Misses       4527     4515      -12     
+ Partials     1626     1605      -21     

Flag	Coverage Δ
unittests	74.70% <85.59%> (+0.17%)	⬆️

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

Impacted Files	Coverage Δ
server/statistics/kind.go	0.00% <0.00%> (ø)
server/cluster/coordinator.go	73.57% <42.85%> (-0.72%)	⬇️
server/api/trend.go	66.19% <50.00%> (ø)
server/schedulers/shuffle_hot_region.go	54.73% <50.00%> (ø)
server/statistics/flowkind.go	83.33% <83.33%> (ø)
server/schedulers/hot_region.go	81.10% <86.66%> (+0.12%)	⬆️
server/schedulers/utils.go	93.63% <100.00%> (+0.52%)	⬆️
server/statistics/hot_peer.go	100.00% <100.00%> (ø)
server/statistics/hot_peer_cache.go	94.14% <100.00%> (+0.96%)	⬆️
server/schedulers/hot_region_config.go	78.72% <0.00%> (-3.20%)	⬇️
... and 15 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b07be86...9e5f8b9. Read the comment docs.

[Yisaer]

Rest LGTM

[lhy1024]

@Yisaer @rleungx PTAL

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• Yisaer
• rleungx

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

The full list of commands accepted by this bot can be found here.

Reviewer can indicate their review by writing /lgtm in a comment.
Reviewer can cancel approval by writing /lgtm cancel in a comment.

[lhy1024]

/merge

[ti-chi-bot]

@lhy1024: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

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 ti-community-infra/tichi repository.

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: a850c8b

[ti-chi-bot]

@lhy1024: Your PR was out of date, I have automatically updated it for you.

At the same time I will also trigger all tests for you:

/run-all-tests

If the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

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 ti-community-infra/tichi repository.

[sonarcloud]

SonarCloud Quality Gate failed.

0 Bugs
0 Vulnerabilities
0 Security Hotspots
5 Code Smells

No Coverage information
7.2% Duplication