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 | 0.6 ± 0.0 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.8 ± 0.0 | 0.8 ± 0.0 | 1.0 ± 0.0 | 1.2 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.4 ± 0.0 | 1.4 ± 0.0 | 1.7 ± 0.0 | 1.9 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 2.8 ± 0.0 | 2.8 ± 0.0 | 3.2 ± 0.1 | 3.5 ± 0.1 |
| 5.0 ± 0.0 | 100.0 ± 0.0 | 7.0 ± 0.1 | 6.9 ± 0.1 | 7.5 ± 0.1 | 7.8 ± 0.1 |
| 9.8 ± 0.1 | 100.0 ± 0.0 | 13.7 ± 0.1 | 13.7 ± 0.1 | 14.4 ± 0.1 | 14.8 ± 0.2 |
| 19.7 ± 0.1 | 99.8 ± 0.0 | 27.3 ± 0.2 | 27.3 ± 0.2 | 28.1 ± 0.2 | 28.6 ± 0.2 |
| 30.9 ± 0.0 | 62.4 ± 0.2 | 42.8 ± 0.0 | 42.7 ± 0.0 | 43.1 ± 0.0 | 43.3 ± 0.0 |
| 33.3 ± 0.0 | 32.9 ± 0.1 | 46.1 ± 0.0 | 46.1 ± 0.0 | 46.4 ± 0.0 | 46.5 ± 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 | 0.4 ± 0.0 | 0.3 ± 0.0 | 0.7 ± 0.1 | 1.1 ± 0.1 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.8 ± 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 ± 0.1 | 2.3 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 2.9 ± 0.0 | 2.8 ± 0.0 | 3.3 ± 0.1 | 3.7 ± 0.1 |
| 4.9 ± 0.0 | 100.0 ± 0.0 | 6.9 ± 0.1 | 6.8 ± 0.1 | 7.6 ± 0.1 | 8.1 ± 0.1 |
| 9.8 ± 0.1 | 100.0 ± 0.0 | 13.8 ± 0.1 | 13.7 ± 0.1 | 14.6 ± 0.1 | 15.2 ± 0.1 |
| 19.5 ± 0.1 | 99.2 ± 0.0 | 27.2 ± 0.1 | 27.2 ± 0.1 | 28.2 ± 0.2 | 28.8 ± 0.2 |
| 29.9 ± 0.0 | 60.2 ± 0.2 | 41.5 ± 0.0 | 41.5 ± 0.0 | 42.1 ± 0.0 | 42.5 ± 0.0 |
| 32.5 ± 0.0 | 32.1 ± 0.0 | 45.1 ± 0.0 | 45.1 ± 0.0 | 45.7 ± 0.0 | 46.0 ± 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 | 0.4 ± 0.0 | 0.3 ± 0.0 | 0.9 ± 0.1 | 1.2 ± 0.0 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.9 ± 0.0 | 0.8 ± 0.0 | 1.4 ± 0.0 | 1.8 ± 0.0 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.6 ± 0.0 | 1.5 ± 0.0 | 2.2 ± 0.1 | 2.6 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 3.0 ± 0.1 | 2.9 ± 0.1 | 3.7 ± 0.1 | 4.2 ± 0.1 |
| 4.9 ± 0.1 | 100.0 ± 0.0 | 7.1 ± 0.1 | 7.0 ± 0.1 | 8.0 ± 0.1 | 8.6 ± 0.1 |
| 9.9 ± 0.0 | 100.0 ± 0.0 | 14.1 ± 0.1 | 14.0 ± 0.1 | 15.2 ± 0.1 | 15.9 ± 0.2 |
| 19.0 ± 0.1 | 96.5 ± 0.1 | 26.7 ± 0.1 | 26.6 ± 0.1 | 28.0 ± 0.1 | 28.8 ± 0.1 |
| 27.6 ± 0.0 | 55.7 ± 0.1 | 38.8 ± 0.0 | 38.7 ± 0.0 | 39.8 ± 0.0 | 40.3 ± 0.0 |
| 30.6 ± 0.0 | 30.1 ± 0.1 | 42.8 ± 0.0 | 42.7 ± 0.0 | 43.7 ± 0.0 | 44.1 ± 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 | 0.4 ± 0.0 | 1.0 ± 0.1 | 1.4 ± 0.1 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.9 ± 0.0 | 0.9 ± 0.0 | 1.6 ± 0.0 | 1.9 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.6 ± 0.0 | 1.5 ± 0.0 | 2.3 ± 0.0 | 2.8 ± 0.0 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 3.1 ± 0.1 | 3.0 ± 0.1 | 3.9 ± 0.1 | 4.5 ± 0.1 |
| 4.9 ± 0.1 | 100.0 ± 0.0 | 7.3 ± 0.1 | 7.2 ± 0.1 | 8.4 ± 0.1 | 9.1 ± 0.1 |
| 9.9 ± 0.1 | 99.9 ± 0.0 | 14.3 ± 0.1 | 14.1 ± 0.1 | 15.7 ± 0.2 | 16.6 ± 0.2 |
| 18.1 ± 0.0 | 91.5 ± 0.3 | 25.8 ± 0.1 | 25.6 ± 0.1 | 27.3 ± 0.1 | 28.2 ± 0.1 |
| 25.2 ± 0.0 | 50.4 ± 0.2 | 35.8 ± 0.0 | 35.6 ± 0.0 | 37.1 ± 0.0 | 37.7 ± 0.0 |
| 28.2 ± 0.0 | 27.7 ± 0.1 | 39.8 ± 0.0 | 39.7 ± 0.0 | 41.0 ± 0.0 | 41.6 ± 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!