Note
For V4.2.0, this parameter is available starting with V4.2.0.
Description
The range_optimizer_max_mem_size parameter limits the memory usage of the Query Range optimizer module.
Privilege requirements
Query the parameter
You can run the
SHOW PARAMETERSstatement or query theGV$OB_PARAMETERSview in thesystenant and user tenants to view the parameter.Modify the parameter
You can modify the parameter in the
systenant and user tenants.
Attributes
| Attribute | Description |
|---|---|
| Type | Capacity |
| Default value | 128M |
| Value range | [0M, +∞)
Note
|
| 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
The range_optimizer_max_mem_size parameter limits the memory usage of the Query Range optimizer module. If the memory usage of this module exceeds the limit, the system will not extract any ranges for the query. For example, a query with a complex predicate that hits the index may still not choose the index if the memory required to extract the Query Range exceeds the limit, and instead will attempt to execute the query on the main table.
Examples
Set the memory available to the Query Range optimizer module to 128 MB.
obclient> ALTER SYSTEM SET range_optimizer_max_mem_size = '128M';