Model
When scaling out mid-query pays
Money cannot move that line. Only reducing the fixed cost can.
- Remaining work
- core-seconds still to do
- Workers
- workers before and after
- Startup
- provisioning, cold caches, no data locality
Worked examples, recomputed
Every number the mechanisms quote for this relationship is recomputed from it, so none of them disagrees with it.
- 60 core-s, 10 → 20 workers saves 3 s against 30 s of startup
- 100 core-s of 1 s tasks → about 10 workers with decent balance
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?