Note
For V4.6.0, this parameter is available starting with V4.6.0.
Description
ob_vector_index_merge_trigger_percentage specifies the maximum percentage of memory used by incremental segments in a partitioned index. When the memory used by incremental segments exceeds this percentage, the system automatically triggers a segment merge to combine the incremental segments with baseline segments.
Applicability
This parameter is applicable only to OceanBase Database in MySQL mode.
Privilege requirements
Query the parameter
You can use the
SHOW PARAMETERSstatement or query theGV$OB_PARAMETERSview in thesystenant or a MySQL user tenant to query this parameter.Modify the parameter
You can modify this parameter in the
systenant or a MySQL user tenant.
Attributes
| Attribute | Description |
|---|---|
| Type | Int |
| Default value | 20 |
| Value range | [0, 100). The unit is percentage. |
| Modifiable | Yes. You can use the ALTER SYSTEM SET statement to modify the parameter. |
| Effective upon OBServer node restart | No. The setting takes effect immediately. |
Considerations
- Default value (20%): The default value is applicable to most scenarios.
- Increase the value: To reduce the frequency of segment merges, especially when the write speed is high.
- Decrease the value: We recommend that you do not decrease the value in most scenarios.
- Set to
0: This is equivalent to using the default value.
Examples
Set the maximum ratio of the memory occupied by the incremental segments to the total memory occupied by the partitioned indexes to 30%.
ALTER SYSTEM SET ob_vector_index_merge_trigger_percentage = 30;
Query the current value of this parameter.
SHOW PARAMETERS LIKE 'ob_vector_index_merge_trigger_percentage';