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Improve index compactor#2465

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lvca merged 1 commit intoArcadeData:mainfrom
gramian:main
Sep 8, 2025
Merged

Improve index compactor#2465
lvca merged 1 commit intoArcadeData:mainfrom
gramian:main

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@gramian
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@gramian gramian commented Sep 3, 2025

What does this PR do?

This change adds a guard to ensure at least one page is compacted.

Related issues

#2434

Additional Notes

This does not resolve the issue but prevents the invalid position exception. The OOM is still present.

Checklist

  • I have run the build using mvn clean package command
  • My unit tests cover both failure and success scenarios

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Summary of Changes

Hello @gramian, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a critical fix to the index compaction process, specifically within the LSMTreeIndexCompactor. The primary goal is to prevent an invalid position exception by guaranteeing that a minimum of one page is always targeted for compaction, even under memory constraints. While this change resolves a specific error, it's noted that it does not fully address the underlying Out-Of-Memory (OOM) issue.

Highlights

  • Index Compaction Logic: Implemented a safeguard in the LSMTreeIndexCompactor to ensure that at least one page is always selected for compaction. This prevents scenarios where pagesToCompact might incorrectly resolve to zero, addressing a potential invalid position exception.
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Code Review

This pull request introduces a safeguard in the LSM Tree index compactor to prevent a potential infinite loop. The change ensures that even when the configured compaction RAM is smaller than a single page size, at least one page is selected for compaction, allowing the process to make progress. This correctly addresses the invalid position exception mentioned in the issue. The logic is sound and the change is a good improvement for the stability of the index compaction process.

Comment on lines +118 to +119
if (pagesToCompact < 1)
pagesToCompact = 1;
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medium

According to common Java style guides, such as the Google Java Style Guide, braces should be used with if statements even when the body contains only a single statement. This improves code clarity and helps prevent potential bugs during future modifications.1

        if (pagesToCompact < 1) {
          pagesToCompact = 1;
        }

Style Guide References

Footnotes

  1. Google Java Style Guide section 4.1.1 recommends using braces for all if, else, for, do, and while statements, even for single-line bodies.

@lvca lvca self-requested a review September 8, 2025 20:30
@lvca lvca modified the milestones: 25.10.1, 25.8.1 Sep 8, 2025
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lvca commented Sep 8, 2025

It looks good to me, approved!

@lvca lvca merged commit b3ba162 into ArcadeData:main Sep 8, 2025
10 of 12 checks passed
@lvca lvca added the bug label Sep 9, 2025
robfrank pushed a commit that referenced this pull request Sep 10, 2025
(cherry picked from commit b3ba162)
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2 participants