One experiment on a CPU-bound query found near-linear scaling in performance by adding CPUs until the I/O subsystem became saturated. At that point, additional CPU resources did not improve performance. The query performs a table scan on an 800MB table with 30 partitions, using 16K I/O. Table 7-3 shows the CPU scaling.
Engines |
Elapsed time, (in seconds) |
CPU utilization |
I/O saturation |
Throughput per device, per second |
---|---|---|---|---|
1 |
207 |
100% |
Not saturated |
.13MB |
2 |
100 |
98.7% |
Not saturated |
.27MB |
4 |
50 |
98% |
Not saturated |
.53MB |
8 |
27 |
93% |
100% saturated |
.99MB |