Note
This parameter is available starting with V4.2.0.
Description
The range_optimizer_max_mem_size parameter specifies the maximum memory size available for the Query Range module.
Privilege requirements
Query the parameter
You can query the
range_optimizer_max_mem_sizeparameter by using theSHOW PARAMETERSstatement or theGV$OB_PARAMETERSview in thesystenant and any user tenant.Modify the parameter
You can modify this parameter in the
systenant and any user tenant.
Attributes
| Attribute | Description |
|---|---|
| Type | Capacity |
| Default value | 128M |
| Value range | [0M, +∞)
NoteFor V4.3.x, the value range of the |
| 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 memory size available for the Query Range module. When the memory used by the Query Range module reaches its limit, the system will not extract any ranges. For example, if a complex predicate hits an index, but the memory required to extract ranges for this complex predicate exceeds the limit, the system will not use the index and will instead access the primary table.
Examples
Set the maximum memory size available for the Query Range module to 128 MB.
obclient> ALTER SYSTEM SET range_optimizer_max_mem_size = '128M';