feat(storage): separate storage databases experimentally

[ijsong]

What this PR does

This PR implemented the idea of separating the storage database, which was proposed by @hungryjang.
It divides storage databases into two parts: data database and commit database. The data part
stores records whose keys are LLSNs and whose values are log data users append. The commit part
stores records whose keys are GLSNs and whose values are LLSNs.

This approach is very performant compared to the previous one. Especially the data part can take
advantage of move compaction dramatically. Empirically throughput can be increased by about 10-20%
and append duration reduced by about 10-20%.
However, it doubles the number of pebble instances. We should configure the storage databases
carefully to overcome this.

[ijsong]

Current dependencies on/for this PR:

• main
  • PR ci(make): increase test timeout and reduce parallelism #409
    • PR perf(storagenode): check log level #411
      • PR perf(storagenode): remove backup from append request #412
        • PR refactor(storagenode): simplify unary RPC logging #413
          • PR perf(storagenode): estimate the number of batchlets #414
    • PR feat(storage): separate storage databases experimentally #410 👈

This comment was auto-generated by Graphite.

[codecov-commenter]

Codecov Report

Patch coverage: 50.72% and project coverage change: +0.16 🎉

Comparison is base (6ccf9ec) 63.60% compared to head (e3fa2f4) 63.76%.

📣 This organization is not using Codecov’s GitHub App Integration. We recommend you install it so Codecov can continue to function properly for your repositories. Learn more

Additional details and impacted files

@@               Coverage Diff                @@
##           test_options     #410      +/-   ##
================================================
+ Coverage         63.60%   63.76%   +0.16%     
================================================
  Files               131      131              
  Lines             17801    17918     +117     
================================================
+ Hits              11322    11426     +104     
- Misses             5937     5949      +12     
- Partials            542      543       +1     

Impacted Files	Coverage Δ
internal/storage/testing.go	18.60% <0.00%> (-0.91%)	⬇️
internal/storage/config.go	51.33% <18.66%> (-12.96%)	⬇️
internal/storage/append_batch.go	76.92% <61.53%> (-5.43%)	⬇️
internal/storage/storage.go	87.45% <74.74%> (+9.52%)	⬆️
internal/storage/recovery_points.go	90.69% <100.00%> (ø)
internal/storage/scanner.go	98.71% <100.00%> (ø)
internal/storagenode/storagenode.go	73.78% <100.00%> (+0.84%)	⬆️
internal/storagenode/volume/volume.go	94.38% <100.00%> (ø)

... and 7 files with indirect coverage changes

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.