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 | 0.6 ± 0.0 | 0.7 ± 0.1 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.6 ± 0.0 | 0.7 ± 0.0 | 1.0 ± 0.0 | 1.2 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.2 ± 0.1 | 1.4 ± 0.1 | 1.7 ± 0.0 | 1.9 ± 0.0 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 2.7 ± 0.0 | 2.7 ± 0.0 | 3.2 ± 0.0 | 3.4 ± 0.0 |
| 4.9 ± 0.1 | 100.0 ± 0.0 | 6.8 ± 0.1 | 6.8 ± 0.1 | 7.4 ± 0.1 | 7.7 ± 0.2 |
| 9.9 ± 0.1 | 100.0 ± 0.0 | 13.7 ± 0.2 | 13.7 ± 0.2 | 14.4 ± 0.2 | 14.8 ± 0.2 |
| 18.8 ± 0.1 | 95.3 ± 0.1 | 26.2 ± 0.1 | 26.2 ± 0.1 | 27.0 ± 0.1 | 27.5 ± 0.1 |
| 25.2 ± 0.0 | 50.6 ± 0.1 | 35.3 ± 0.0 | 35.3 ± 0.0 | 36.0 ± 0.0 | 36.5 ± 0.0 |
| 27.0 ± 0.0 | 26.4 ± 0.1 | 37.9 ± 0.0 | 37.8 ± 0.0 | 38.5 ± 0.0 | 39.0 ± 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 ± 0.2 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.6 ± 0.0 | 0.7 ± 0.0 | 1.1 ± 0.1 | 1.5 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.2 ± 0.0 | 1.4 ± 0.0 | 1.8 ± 0.0 | 2.2 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 2.7 ± 0.0 | 2.8 ± 0.0 | 3.3 ± 0.0 | 3.6 ± 0.1 |
| 4.9 ± 0.1 | 100.0 ± 0.0 | 6.9 ± 0.1 | 6.9 ± 0.1 | 7.6 ± 0.1 | 8.1 ± 0.2 |
| 9.9 ± 0.1 | 100.0 ± 0.0 | 13.8 ± 0.1 | 13.8 ± 0.1 | 14.7 ± 0.2 | 15.3 ± 0.3 |
| 18.7 ± 0.1 | 94.8 ± 0.1 | 26.1 ± 0.1 | 26.1 ± 0.1 | 27.0 ± 0.1 | 27.7 ± 0.1 |
| 24.9 ± 0.0 | 50.1 ± 0.2 | 35.0 ± 0.0 | 34.9 ± 0.0 | 35.8 ± 0.0 | 36.5 ± 0.0 |
| 26.7 ± 0.0 | 26.2 ± 0.0 | 37.5 ± 0.0 | 37.4 ± 0.0 | 38.4 ± 0.0 | 38.9 ± 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 | 1.0 ± 0.1 | 1.3 ± 0.1 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.6 ± 0.0 | 0.7 ± 0.0 | 1.3 ± 0.0 | 1.7 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.3 ± 0.0 | 1.4 ± 0.0 | 2.0 ± 0.0 | 2.4 ± 0.1 |
| 2.0 ± 0.1 | 100.0 ± 0.0 | 2.8 ± 0.1 | 2.8 ± 0.1 | 3.5 ± 0.1 | 4.0 ± 0.1 |
| 5.0 ± 0.0 | 100.0 ± 0.0 | 7.0 ± 0.1 | 7.0 ± 0.1 | 7.9 ± 0.1 | 8.5 ± 0.1 |
| 9.9 ± 0.1 | 100.0 ± 0.0 | 14.0 ± 0.1 | 13.9 ± 0.1 | 15.0 ± 0.1 | 15.6 ± 0.1 |
| 18.5 ± 0.0 | 93.2 ± 0.1 | 26.0 ± 0.0 | 25.9 ± 0.0 | 27.2 ± 0.1 | 28.0 ± 0.1 |
| 24.1 ± 0.0 | 48.5 ± 0.1 | 34.2 ± 0.0 | 34.1 ± 0.0 | 35.4 ± 0.0 | 36.1 ± 0.0 |
| 26.0 ± 0.0 | 25.5 ± 0.1 | 36.8 ± 0.0 | 36.7 ± 0.0 | 37.9 ± 0.0 | 38.5 ± 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 ± 0.1 | 1.3 ± 0.1 |
| 0.5 ± 0.0 | 100.0 ± 0.0 | 0.7 ± 0.0 | 0.7 ± 0.0 | 1.4 ± 0.0 | 1.8 ± 0.1 |
| 1.0 ± 0.0 | 100.0 ± 0.0 | 1.3 ± 0.0 | 1.5 ± 0.0 | 2.2 ± 0.0 | 2.5 ± 0.1 |
| 2.0 ± 0.0 | 100.0 ± 0.0 | 2.9 ± 0.0 | 2.9 ± 0.0 | 3.7 ± 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 | 8.7 ± 0.1 |
| 9.9 ± 0.1 | 100.0 ± 0.0 | 14.1 ± 0.1 | 14.0 ± 0.1 | 15.3 ± 0.1 | 16.0 ± 0.1 |
| 18.1 ± 0.1 | 91.7 ± 0.1 | 25.8 ± 0.1 | 25.6 ± 0.1 | 27.2 ± 0.1 | 28.2 ± 0.1 |
| 23.4 ± 0.0 | 46.9 ± 0.2 | 33.4 ± 0.0 | 33.3 ± 0.0 | 34.8 ± 0.0 | 35.6 ± 0.0 |
| 25.1 ± 0.0 | 24.6 ± 0.1 | 35.9 ± 0.0 | 35.8 ± 0.0 | 37.2 ± 0.0 | 37.9 ± 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!