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 | 0.6 ± 0.0 | 0.7 ± 0.0 | 1.0 ± 0.0 | 1.1 ± 0.0 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.2 ± 0.1 | 1.3 ± 0.0 | 1.7 ± 0.1 | 1.9 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 2.7 ± 0.0 | 2.8 ± 0.0 | 3.2 ± 0.1 | 3.4 ± 0.1 |
| 4.9 ± 0.1 | 100.0 ± 0.0 | 6.8 ± 0.1 | 6.8 ± 0.1 | 7.4 ± 0.1 | 7.7 ± 0.1 |
| 9.8 ± 0.1 | 100.0 ± 0.0 | 13.6 ± 0.1 | 13.6 ± 0.1 | 14.3 ± 0.1 | 14.6 ± 0.1 |
| 19.7 ± 0.2 | 100.0 ± 0.0 | 27.2 ± 0.2 | 27.2 ± 0.3 | 28.0 ± 0.2 | 28.5 ± 0.1 |
| 35.8 ± 0.0 | 72.9 ± 0.2 | 49.5 ± 0.0 | 49.4 ± 0.0 | 49.8 ± 0.0 | 50.0 ± 0.0 |
| 39.3 ± 0.0 | 39.2 ± 0.1 | 54.2 ± 0.0 | 54.2 ± 0.0 | 54.5 ± 0.0 | 54.6 ± 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 ± 0.0 | 1.0 ± 0.1 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.6 ± 0.0 | 0.7 ± 0.0 | 1.1 ± 0.0 | 1.4 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.2 ± 0.0 | 1.4 ± 0.0 | 1.8 ± 0.1 | 2.2 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 2.7 ± 0.1 | 2.7 ± 0.1 | 3.3 ± 0.0 | 3.6 ± 0.0 |
| 4.9 ± 0.1 | 100.0 ± 0.0 | 6.9 ± 0.1 | 6.9 ± 0.2 | 7.5 ± 0.2 | 7.9 ± 0.2 |
| 9.9 ± 0.1 | 100.0 ± 0.0 | 13.7 ± 0.1 | 13.7 ± 0.1 | 14.5 ± 0.1 | 15.0 ± 0.1 |
| 19.8 ± 0.1 | 100.0 ± 0.0 | 27.3 ± 0.1 | 27.4 ± 0.1 | 28.3 ± 0.1 | 28.8 ± 0.2 |
| 35.4 ± 0.1 | 71.9 ± 0.1 | 48.9 ± 0.0 | 48.9 ± 0.0 | 49.5 ± 0.0 | 49.8 ± 0.0 |
| 38.7 ± 0.0 | 38.6 ± 0.1 | 53.6 ± 0.0 | 53.6 ± 0.0 | 54.1 ± 0.0 | 54.4 ± 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 | 0.9 ± 0.1 | 1.3 ± 0.1 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.6 ± 0.0 | 0.7 ± 0.0 | 1.3 ± 0.1 | 1.6 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.3 ± 0.0 | 1.4 ± 0.0 | 2.0 ± 0.0 | 2.4 ± 0.0 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 2.8 ± 0.0 | 2.8 ± 0.0 | 3.5 ± 0.1 | 3.9 ± 0.1 |
| 4.9 ± 0.0 | 100.0 ± 0.0 | 7.0 ± 0.0 | 6.9 ± 0.0 | 7.8 ± 0.1 | 8.3 ± 0.1 |
| 9.8 ± 0.0 | 100.0 ± 0.0 | 13.8 ± 0.1 | 13.7 ± 0.0 | 14.8 ± 0.1 | 15.4 ± 0.1 |
| 19.6 ± 0.2 | 100.0 ± 0.0 | 27.4 ± 0.2 | 27.3 ± 0.2 | 28.5 ± 0.3 | 29.1 ± 0.3 |
| 34.3 ± 0.1 | 69.5 ± 0.2 | 47.8 ± 0.0 | 47.7 ± 0.0 | 48.6 ± 0.0 | 49.1 ± 0.0 |
| 37.6 ± 0.0 | 37.4 ± 0.1 | 52.3 ± 0.0 | 52.3 ± 0.0 | 53.1 ± 0.0 | 53.5 ± 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 | 0.7 ± 0.0 | 0.8 ± 0.0 | 1.5 ± 0.1 | 1.8 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.4 ± 0.0 | 1.5 ± 0.0 | 2.1 ± 0.0 | 2.5 ± 0.0 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 2.9 ± 0.1 | 2.9 ± 0.1 | 3.6 ± 0.1 | 4.1 ± 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 | 14.0 ± 0.1 | 13.9 ± 0.1 | 15.1 ± 0.1 | 15.8 ± 0.1 |
| 19.6 ± 0.1 | 99.9 ± 0.0 | 27.6 ± 0.1 | 27.5 ± 0.1 | 28.9 ± 0.1 | 29.7 ± 0.1 |
| 33.1 ± 0.0 | 67.2 ± 0.2 | 46.5 ± 0.0 | 46.4 ± 0.0 | 47.6 ± 0.0 | 48.1 ± 0.0 |
| 36.2 ± 0.0 | 36.0 ± 0.1 | 50.9 ± 0.0 | 50.8 ± 0.0 | 51.8 ± 0.0 | 52.3 ± 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!