Note
For V4.3.5, this parameter is available starting with V4.3.5 BP4.
Description
approx_count_distinct_precision specifies the precision of the result of the approx_count_distinct function.
Privilege requirements
Querying the parameter
You can run the
SHOW PARAMETERSstatement or query theGV$OB_PARAMETERSview in thesystenant or any user tenant to query this parameter.Modifying the parameter
You can modify this parameter in the
systenant or any user tenant.
Attributes
Attribute |
Description |
|---|---|
| Parameter type | Integer |
| Default value | 10 |
| Value range | [4, 16] |
| Modifiability | Yes. You can modify this parameter by using the ALTER SYSTEM SET statement. |
| Effective only after OBServer restart | No |
Examples
Run the following statement to set the calculation precision of the cardinality estimation function to 10.
obclient> ALTER SYSTEM SET approx_count_distinct_precision = 10;