Note
This variable is available starting with OceanBase Database V4.3.5 BP1.
Description
The ob_ivf_nprobes variable specifies the number of nearest cluster centers to search during a vector index query. This variable affects the performance and recall rate of IVF queries: the larger the value, the higher the recall rate, but the longer the search time.
Applicability
This variable is applicable only to OceanBase Database's MySQL-compatible mode.
Privilege requirements
Query variables
Both the
systenant and all user tenants can use theSHOW VARIABLESstatement or theinformation_schema.SESSION_VARIABLESview (MySQL mode) to view the values of session system variables.Modify variables
Both the
systenant and all MySQL user tenants can directly modify the values of session system variables of the tenant.
Attributes
| Attribute | Description |
|---|---|
| Parameter type | Int |
| Default value | 8 |
| Value range | [1,65536] |
| Effective scope | Session |
| Modifiable | Yes. You can modify this variable by using the SET statement. |
Examples
Set this variable so that the current query searches 10 nearest cluster centers.
obclient> SET ob_ivf_nprobes = 10;