Note
For V4.2.0, this parameter is available starting with V4.2.0.
Description
range_optimizer_max_mem_size specifies the maximum amount of memory that can be used by the Query Range module.
Privilege requirements
Query the parameter
systenant and all user tenants can query the value of this parameter by using theSHOW PARAMETERSstatement or theGV$OB_PARAMETERSview.Modify the parameter
The
systenant and user tenants can modify this parameter.
Attributes
| Attribute | Description |
|---|---|
| Type | Capacity |
| Default value | 128M |
| Value range | [0M, +∞)
NoteFor V4.3.x, the valid value range was changed from [16M, 1G] to [0M, +∞) starting with V4.3.0. |
| 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
This parameter specifies the maximum amount of memory that can be used by the Query Range module. If the Query Range module uses up its maximum memory, the system will not extract any ranges from the query. For example, if a complex predicate hits an index, but the system cannot extract a range from the complex predicate due to the memory usage limit, it will choose the table instead of the index.
Examples
Set the maximum amount of memory for the Query Range module to 128 MB.
obclient> ALTER SYSTEM SET range_optimizer_max_mem_size = '128M';