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 | 0.3 ± 0.0 | 0.3 ± 0.0 | 0.5 ± 0.0 | 0.7 ± 0.0 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.7 ± 0.0 | 0.7 ± 0.0 | 1.0 ± 0.0 | 1.2 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.4 ± 0.0 | 1.4 ± 0.0 | 1.8 ± 0.0 | 2.0 ± 0.0 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 2.8 ± 0.0 | 2.8 ± 0.0 | 3.2 ± 0.0 | 3.4 ± 0.0 |
| 4.9 ± 0.0 | 100.0 ± 0.0 | 6.9 ± 0.0 | 6.9 ± 0.0 | 7.5 ± 0.1 | 7.8 ± 0.1 |
| 9.8 ± 0.0 | 99.8 ± 0.0 | 13.7 ± 0.0 | 13.7 ± 0.1 | 14.5 ± 0.1 | 15.0 ± 0.1 |
| 16.7 ± 0.0 | 84.5 ± 0.3 | 23.4 ± 0.1 | 23.3 ± 0.1 | 24.1 ± 0.1 | 24.5 ± 0.1 |
| 20.4 ± 0.0 | 40.9 ± 0.2 | 28.7 ± 0.0 | 28.6 ± 0.0 | 29.3 ± 0.0 | 29.7 ± 0.0 |
| 21.7 ± 0.0 | 21.2 ± 0.0 | 30.6 ± 0.0 | 30.5 ± 0.0 | 31.2 ± 0.0 | 31.5 ± 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 | 0.3 ± 0.0 | 0.3 ± 0.0 | 0.6 ± 0.1 | 1.0 ± 0.1 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.7 ± 0.0 | 0.8 ± 0.0 | 1.1 ± 0.0 | 1.5 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.5 ± 0.0 | 1.5 ± 0.0 | 1.9 ± 0.0 | 2.3 ± 0.1 |
| 1.9 ± 0.0 | 100.0 ± 0.0 | 2.8 ± 0.1 | 2.8 ± 0.1 | 3.3 ± 0.1 | 3.7 ± 0.1 |
| 5.0 ± 0.1 | 100.0 ± 0.0 | 7.0 ± 0.1 | 6.9 ± 0.1 | 7.7 ± 0.1 | 8.2 ± 0.0 |
| 9.8 ± 0.1 | 99.6 ± 0.1 | 13.8 ± 0.1 | 13.8 ± 0.1 | 14.7 ± 0.1 | 15.3 ± 0.1 |
| 16.4 ± 0.1 | 82.9 ± 0.1 | 23.1 ± 0.1 | 23.0 ± 0.0 | 24.0 ± 0.1 | 24.7 ± 0.1 |
| 20.1 ± 0.0 | 40.1 ± 0.1 | 28.3 ± 0.0 | 28.3 ± 0.0 | 29.2 ± 0.0 | 29.7 ± 0.0 |
| 21.4 ± 0.0 | 20.9 ± 0.0 | 30.2 ± 0.0 | 30.2 ± 0.0 | 31.0 ± 0.0 | 31.5 ± 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 | 0.3 ± 0.0 | 0.3 ± 0.0 | 0.8 ± 0.1 | 1.2 ± 0.1 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.7 ± 0.0 | 0.8 ± 0.0 | 1.3 ± 0.0 | 1.7 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.5 ± 0.0 | 1.5 ± 0.0 | 2.2 ± 0.0 | 2.6 ± 0.1 |
| 1.9 ± 0.1 | 100.0 ± 0.0 | 2.9 ± 0.1 | 2.8 ± 0.1 | 3.6 ± 0.1 | 4.1 ± 0.1 |
| 4.9 ± 0.0 | 100.0 ± 0.0 | 7.1 ± 0.1 | 7.0 ± 0.1 | 8.0 ± 0.1 | 8.6 ± 0.1 |
| 9.9 ± 0.1 | 99.3 ± 0.1 | 14.0 ± 0.1 | 13.9 ± 0.1 | 15.1 ± 0.1 | 15.9 ± 0.1 |
| 15.9 ± 0.1 | 79.9 ± 0.2 | 22.6 ± 0.1 | 22.4 ± 0.1 | 23.8 ± 0.1 | 24.6 ± 0.1 |
| 19.3 ± 0.0 | 38.6 ± 0.2 | 27.5 ± 0.0 | 27.4 ± 0.0 | 28.6 ± 0.0 | 29.3 ± 0.0 |
| 20.7 ± 0.0 | 20.2 ± 0.0 | 29.5 ± 0.0 | 29.4 ± 0.0 | 30.5 ± 0.0 | 31.1 ± 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 | 0.4 ± 0.0 | 0.3 ± 0.0 | 1.1 ± 0.0 | 1.4 ± 0.1 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.8 ± 0.0 | 0.8 ± 0.0 | 1.5 ± 0.0 | 1.8 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.6 ± 0.0 | 1.5 ± 0.0 | 2.3 ± 0.0 | 2.7 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 3.0 ± 0.1 | 2.9 ± 0.0 | 3.8 ± 0.1 | 4.3 ± 0.1 |
| 4.9 ± 0.1 | 100.0 ± 0.0 | 7.2 ± 0.1 | 7.1 ± 0.1 | 8.2 ± 0.1 | 9.0 ± 0.1 |
| 9.7 ± 0.0 | 98.9 ± 0.0 | 14.1 ± 0.1 | 13.9 ± 0.1 | 15.3 ± 0.1 | 16.3 ± 0.1 |
| 15.2 ± 0.0 | 76.8 ± 0.2 | 21.9 ± 0.0 | 21.7 ± 0.0 | 23.4 ± 0.0 | 24.4 ± 0.1 |
| 18.4 ± 0.0 | 36.7 ± 0.1 | 26.5 ± 0.0 | 26.4 ± 0.0 | 27.8 ± 0.0 | 28.6 ± 0.0 |
| 19.9 ± 0.0 | 19.3 ± 0.0 | 28.6 ± 0.0 | 28.4 ± 0.0 | 29.8 ± 0.0 | 30.4 ± 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!