Commit Overhead vs Throughput
Commit Overhead vs Throughput
Analysis of commit protocol overhead as percentage of total transaction time.
Overhead = (commit_latency / total_latency) × 100
This represents time spent in retries, exponential backoff, and manifest I/O.
Values shown as mean ± standard deviation across seeds.
real_conflict_probability = 0.0
| Throughput (c/s) | Success Rate (%) | Mean Overhead (%) | P50 Overhead (%) | P95 Overhead (%) | P99 Overhead (%) |
|---|---|---|---|---|---|
| 0.2 ± 0.0 | 100.0 ± 0.0 | 0.4 ± 0.0 | 0.4 ± 0.0 | 0.6 ± 0.0 | 0.7 ± 0.0 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.8 ± 0.0 | 0.8 ± 0.0 | 1.0 ± 0.0 | 1.2 ± 0.0 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.5 ± 0.0 | 1.5 ± 0.0 | 1.8 ± 0.0 | 2.0 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 2.9 ± 0.0 | 2.8 ± 0.0 | 3.3 ± 0.1 | 3.6 ± 0.1 |
| 4.9 ± 0.0 | 100.0 ± 0.0 | 7.0 ± 0.1 | 6.9 ± 0.1 | 7.5 ± 0.1 | 7.9 ± 0.1 |
| 9.7 ± 0.1 | 98.8 ± 0.1 | 13.6 ± 0.1 | 13.6 ± 0.1 | 14.4 ± 0.2 | 14.8 ± 0.1 |
| 15.1 ± 0.0 | 76.2 ± 0.3 | 21.1 ± 0.1 | 21.1 ± 0.1 | 21.6 ± 0.0 | 21.9 ± 0.0 |
| 17.6 ± 0.0 | 35.0 ± 0.0 | 24.5 ± 0.0 | 24.5 ± 0.0 | 24.9 ± 0.0 | 25.1 ± 0.0 |
| 18.6 ± 0.0 | 18.1 ± 0.0 | 25.9 ± 0.0 | 25.9 ± 0.0 | 26.3 ± 0.0 | 26.4 ± 0.0 |
real_conflict_probability = 0.1
| Throughput (c/s) | Success Rate (%) | Mean Overhead (%) | P50 Overhead (%) | P95 Overhead (%) | P99 Overhead (%) |
|---|---|---|---|---|---|
| 0.2 ± 0.0 | 100.0 ± 0.0 | 0.4 ± 0.0 | 0.4 ± 0.0 | 0.7 ± 0.1 | 1.1 ± 0.2 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.9 ± 0.0 | 0.8 ± 0.0 | 1.2 ± 0.0 | 1.7 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.6 ± 0.0 | 1.5 ± 0.0 | 2.0 ± 0.0 | 2.5 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 2.9 ± 0.1 | 2.9 ± 0.0 | 3.5 ± 0.1 | 4.0 ± 0.1 |
| 5.0 ± 0.1 | 100.0 ± 0.0 | 7.1 ± 0.1 | 7.0 ± 0.1 | 7.9 ± 0.1 | 8.5 ± 0.2 |
| 9.6 ± 0.1 | 97.7 ± 0.1 | 13.6 ± 0.1 | 13.6 ± 0.1 | 14.6 ± 0.1 | 15.2 ± 0.1 |
| 14.5 ± 0.0 | 73.6 ± 0.4 | 20.4 ± 0.0 | 20.3 ± 0.0 | 21.2 ± 0.0 | 21.8 ± 0.0 |
| 17.2 ± 0.0 | 34.2 ± 0.1 | 24.1 ± 0.0 | 24.0 ± 0.0 | 24.8 ± 0.0 | 25.3 ± 0.0 |
| 18.3 ± 0.0 | 17.8 ± 0.1 | 25.6 ± 0.0 | 25.5 ± 0.0 | 26.3 ± 0.0 | 26.7 ± 0.0 |
real_conflict_probability = 0.3
| Throughput (c/s) | Success Rate (%) | Mean Overhead (%) | P50 Overhead (%) | P95 Overhead (%) | P99 Overhead (%) |
|---|---|---|---|---|---|
| 0.2 ± 0.0 | 100.0 ± 0.0 | 0.5 ± 0.0 | 0.4 ± 0.0 | 1.0 ± 0.1 | 1.3 ± 0.2 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.9 ± 0.0 | 0.8 ± 0.0 | 1.5 ± 0.0 | 2.1 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.7 ± 0.0 | 1.6 ± 0.0 | 2.4 ± 0.1 | 3.1 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 3.1 ± 0.0 | 2.9 ± 0.0 | 3.9 ± 0.0 | 4.7 ± 0.1 |
| 4.9 ± 0.1 | 99.7 ± 0.1 | 7.3 ± 0.1 | 7.1 ± 0.1 | 8.4 ± 0.1 | 9.4 ± 0.1 |
| 9.2 ± 0.1 | 93.6 ± 0.2 | 13.4 ± 0.1 | 13.2 ± 0.1 | 14.7 ± 0.1 | 15.6 ± 0.1 |
| 13.3 ± 0.0 | 67.0 ± 0.3 | 19.1 ± 0.0 | 18.9 ± 0.1 | 20.3 ± 0.1 | 21.1 ± 0.1 |
| 16.1 ± 0.0 | 32.0 ± 0.1 | 22.8 ± 0.0 | 22.7 ± 0.0 | 23.9 ± 0.0 | 24.6 ± 0.0 |
| 17.4 ± 0.0 | 16.9 ± 0.0 | 24.7 ± 0.0 | 24.6 ± 0.0 | 25.8 ± 0.0 | 26.4 ± 0.0 |
real_conflict_probability = 0.5
| Throughput (c/s) | Success Rate (%) | Mean Overhead (%) | P50 Overhead (%) | P95 Overhead (%) | P99 Overhead (%) |
|---|---|---|---|---|---|
| 0.2 ± 0.0 | 100.0 ± 0.0 | 0.5 ± 0.0 | 0.4 ± 0.0 | 1.1 ± 0.1 | 1.6 ± 0.2 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 1.0 ± 0.0 | 0.9 ± 0.0 | 1.7 ± 0.1 | 2.3 ± 0.2 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.7 ± 0.0 | 1.6 ± 0.0 | 2.6 ± 0.0 | 3.3 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 3.3 ± 0.0 | 3.1 ± 0.0 | 4.4 ± 0.1 | 5.3 ± 0.1 |
| 4.9 ± 0.0 | 98.2 ± 0.2 | 7.5 ± 0.0 | 7.2 ± 0.0 | 9.1 ± 0.1 | 10.3 ± 0.1 |
| 8.5 ± 0.0 | 86.2 ± 0.3 | 12.7 ± 0.1 | 12.4 ± 0.1 | 14.4 ± 0.1 | 15.6 ± 0.1 |
| 12.0 ± 0.0 | 60.4 ± 0.3 | 17.6 ± 0.0 | 17.3 ± 0.0 | 19.2 ± 0.0 | 20.1 ± 0.1 |
| 14.6 ± 0.0 | 29.1 ± 0.1 | 21.1 ± 0.0 | 21.0 ± 0.0 | 22.6 ± 0.0 | 23.5 ± 0.0 |
| 16.1 ± 0.0 | 15.7 ± 0.0 | 23.2 ± 0.0 | 23.0 ± 0.0 | 24.6 ± 0.0 | 25.4 ± 0.0 |
Interpretation
- Low overhead (<10%): System operating efficiently, minimal contention
- Medium overhead (10-30%): Moderate contention, acceptable performance
- High overhead (30-50%): High contention, commit protocol becoming significant
- Very high overhead (>50%): Commit protocol dominates, system saturated
Values shown as mean ± standard deviation across multiple seeds. At saturation, overhead can exceed 50%, meaning more time is spent retrying commits than executing transactions!