# Expected Diagnosis: progressive-resource-growth-during-steady-workload

The expected result should converge on the case-specific mechanism below while
keeping conclusions bounded by the collected evidence.

## Expected conclusion

TiDB v8.1.1 failed to release entries from the statistics usage delta map because the hourly dumpStatsMaxDuration cleanup path was unreachable. The retained map grew the heap, increased Go GC CPU, and made per-statement CPU rise with process uptime; restart only cleared the accumulated state. The defect is fixed by the statistics cleanup change shipped in v8.5.6 and requires upgrade or a v8.1 hotfix.

## Required evidence chain

- Establish that memory, GC CPU, and per-statement CPU grow with process uptime while workload remains broadly stable, and that restart resets the trend.
- Use heap/profile or statistics evidence to identify retained statistics usage delta-map entries rather than attributing the incident to generic traffic growth.
- Explain the causal chain from retained map entries to heap growth, greater Go GC work, and higher CPU cost.
- Recommend upgrading to a release containing the cleanup fix or applying the corresponding hotfix; restart is only a temporary mitigation.