Summary information |
|
|---|---|
Default value |
1000 |
Range of values |
0 - 65534 |
Status |
Dynamic |
Display level |
Comprehensive |
Required role |
System administrator |
Configuration group |
|
cost of a cpu unit specifies the cost of a single CPU operation.
The cost of a serial plan in the optimizer is described by this formula:
Cost = PIO X estimated_pio + LIO X estimated_lio + 100 X estimated_cpu / CPU
Where the default values of:
PIO = 25
LIO = 2
CPU = 1000
If your Adaptive Server has sufficient memory, then all tables exist in memory, and a value of 0 for cost of a physical io is appropriate.
If you CPU is fast enough that the value for cost of a cpu unit is not a issue, then the formula for CPU combining with 2 LIO and 25 PIO (the default values) is:
CPU X 100/configuration_value
The default value for configuration_value is 1000
As the you increase the value for cost of a cpu unit, this formula reduces the impact of CPU on cost
