# Expected Diagnosis: database-time-spike-with-storage-read-wait

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

## Expected conclusion

The short database-time spike was driven by a transient RocksDB cache-miss period that increased TiKV disk read wait for copr-select requests. The memory-quota-killed queries occurred at other times and were not the direct trigger for this narrow spike. The diagnosis should remain bounded because similar cache-hit dips did not always produce database-time spikes.

## Required evidence chain

- Align the database-time spike with TiKV disk read wait and copr-select disk IO in the same narrow window.
- Identify transient RocksDB cache misses as the immediate mechanism.
- Separate memory-quota-killed queries that occurred outside the incident window from the primary cause.
- Keep confidence bounded because cache-hit degradation did not always produce the same symptom, and recommend continued correlation monitoring.