RockteMQ-AI commented on issue #11321:
URL: https://github.com/apache/rocketmq/issues/11321#issuecomment-6110394743
**Issue Evaluation**
Category: `type/bug` | Status: **Confirmed**
The loop condition `i > 0` in `StatisticsBrief.getTPValue` (line 115)
excludes bucket 0 from the percentile scan. When all samples fall into the
first bucket, the loop never accumulates enough to exceed `excludes`, and the
method falls through to `return 0`.
**Root Cause:** Off-by-one in the loop bound — should be `i >= 0` instead of
`i > 0`.
**Impact:** Any metric whose whole population sits in the first latency
bucket reports zero percentiles (TP50, TP99, TP999 all return 0). This affects
`StatisticsBriefInterceptor` / `StatisticsManager` percentile output, making
latency metrics silently wrong for low-latency workloads.
**Severity:** Medium — incorrect metrics output, not data loss, but can
mislead capacity planning and SLA monitoring.
**Reproduction:** Sample value `5` one hundred times with meta `{{100, 10}}`
— `getTPValue(0.99f)` returns 0 instead of the expected bucket-0 upper bound.
An automated fix proposal can be generated. Reply `/approve` to proceed with
PR generation.
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*Automated evaluation by RocketMQ-AI*
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