Model
Restarting the whole query
The model stops being practical once nTλ approaches 1.
- Tasks
- tasks in the query
- Task duration
- hours each task runs
- Failure rate
- failures per task-hour
How it behaves
One input on the horizontal axis, the others held fixed.
Data table
| n · T · λ | Expected attempts |
|---|---|
| 0 | 1× |
| 0.063 | 1.06× |
| 0.125 | 1.13× |
| 0.188 | 1.21× |
| 0.25 | 1.28× |
| 0.313 | 1.37× |
| 0.375 | 1.45× |
| 0.438 | 1.55× |
| 0.5 | 1.65× |
| 0.563 | 1.76× |
| 0.625 | 1.87× |
| 0.688 | 1.99× |
| 0.75 | 2.12× |
| 0.813 | 2.25× |
| 0.875 | 2.4× |
| 0.938 | 2.55× |
| 1 | 2.72× |
| 1.06 | 2.89× |
| 1.13 | 3.08× |
| 1.19 | 3.28× |
| 1.25 | 3.49× |
| 1.31 | 3.72× |
| 1.38 | 3.96× |
| 1.44 | 4.21× |
| 1.5 | 4.48× |
| 1.56 | 4.77× |
| 1.63 | 5.08× |
| 1.69 | 5.41× |
| 1.75 | 5.75× |
| 1.81 | 6.13× |
| 1.88 | 6.52× |
| 1.94 | 6.94× |
| 2 | 7.39× |
| 2.06 | 7.87× |
| 2.13 | 8.37× |
| 2.19 | 8.91× |
| 2.25 | 9.49× |
| 2.31 | 10.1× |
| 2.38 | 10.8× |
| 2.44 | 11.4× |
| 2.5 | 12.2× |
| 2.56 | 13× |
| 2.63 | 13.8× |
| 2.69 | 14.7× |
| 2.75 | 15.6× |
| 2.81 | 16.7× |
| 2.88 | 17.7× |
| 2.94 | 18.9× |
| 3 | 20.1× |
| 3.06 | 21.4× |
| 3.13 | 22.8× |
| 3.19 | 24.2× |
| 3.25 | 25.8× |
| 3.31 | 27.5× |
| 3.38 | 29.2× |
| 3.44 | 31.1× |
| 3.5 | 33.1× |
| 3.56 | 35.3× |
| 3.63 | 37.5× |
| 3.69 | 39.9× |
| 3.75 | 42.5× |
| 3.81 | 45.3× |
| 3.88 | 48.2× |
| 3.94 | 51.3× |
| 4 | 54.6× |
| 4.06 | 58.1× |
| 4.13 | 61.9× |
| 4.19 | 65.9× |
| 4.25 | 70.1× |
| 4.31 | 74.6× |
| 4.38 | 79.4× |
| 4.44 | 84.6× |
| 4.5 | 90× |
| 4.56 | 95.8× |
| 4.63 | 102× |
| 4.69 | 109× |
| 4.75 | 116× |
| 4.81 | 123× |
| 4.88 | 131× |
| 4.94 | 139× |
| 5 | 148× |
Worked examples, recomputed
Every number the mechanisms quote for this relationship is recomputed from it, so none of them disagrees with it.
Where it appears
Each mechanism states it in its own names. The general symbol each name stands for is shown with it.
- Execution Engine Runtime
Once a query plan is chosen, why does the machine still sit idle, and what does each mechanism of a query runtime pay to buy that idle time back?