Cold data control may skip the group with the highest threshold

[yuluo-yx]

Description

ColdDataCgCtrService sorts configured thresholds by subtracting two long values and narrowing the result to int. A large threshold delta can overflow the comparator and place the largest threshold after smaller entries. Because only three groups are decelerated per cycle, the group with the highest threshold can be skipped.

Expected behavior

Sort thresholds with Long.compare so the three largest eligible groups are always processed.

[RockteMQ-AI]

Issue Evaluation

Category: type/bug | Status: Confirmed

The issue is valid. ColdDataCgCtrService sorts thresholds by subtracting two long values and narrowing to int. A large threshold delta overflows the comparator, placing the highest threshold after smaller entries. Since only three groups are decelerated per cycle, the group with the highest threshold can be skipped.

Root Cause: (int)(a - b) comparator pattern on long threshold values.
Impact: Cold data control — groups with the highest thresholds may never be processed.
Severity: medium

Recommended fix: Replace with Long.compare(a, b) for overflow-safe sorting.

An automated fix proposal can be generated. Reply /approve to proceed with PR generation.

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Automated evaluation by RockteMQ-AI