etcdserver: compact raft log entries more frequently

[clement2026]

Part of #17098

Goal

Compact raft log more frequently to save memory.

Key Changes

• Added a new function maybeCompactRaftLog to handle raft log compaction.
• Introduce 2 variables: CompactRaftLogEveryNApplies and DefaultCompactRaftLogEveryNApplies to control how frequently the raft log is compacted.
• Fix a test

TODO

• [ ] Add tests for the changes
• [ ] Run benchmarks

[k8s-ci-robot]

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[k8s-ci-robot]

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[codecov-commenter]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 68.81%. Comparing base (59cfd7a) to head (273905b). :warning: Report is 2106 commits behind head on main.

:warning: Current head 273905b differs from pull request most recent head f1a76a2

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Additional details and impacted files

Files with missing lines	Coverage Δ
server/config/config.go	79.76% <ø> (ø)
server/etcdserver/server.go	81.48% <100.00%> (+0.13%)	:arrow_up:

... and 14 files with indirect coverage changes

@@            Coverage Diff             @@
##             main   #18622      +/-   ##
==========================================
+ Coverage   68.79%   68.81%   +0.01%     
==========================================
  Files         420      420              
  Lines       35522    35532      +10     
==========================================
+ Hits        24438    24451      +13     
+ Misses       9657     9654       -3     
  Partials     1427     1427              

---

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[serathius]

This change does to many things, there are two changes here that should be independent:

• Separate maybeCompactRaftLog function allowing us to compact log independently from snapshots.
• Run compaction more frequently. As currently compacti is dependent on snapshot, we would first need to confirm that we are ok with lower number of entries.

[clement2026]

Sure. I'll break down this PR.

[k8s-ci-robot]

PR needs rebase.

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This issue has been automatically marked as stale because it has not had recent activity. It will be closed after 21 days if no further activity occurs. Thank you for your contributions.

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed after 21 days if no further activity occurs. Thank you for your contributions.

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed after 21 days if no further activity occurs. Thank you for your contributions.