Note
This parameter was introduced in V4.2.0.
Description
The range_optimizer_max_mem_size parameter specifies the maximum memory size that the Query Range module can use.
Privilege requirements
Query the parameter
The
systenant and all user tenants can use theSHOW PARAMETERSstatement or theGV$OB_PARAMETERSview to query this parameter.Modify the parameter
The
systenant and user tenants can modify this parameter.
Attributes
| Attribute | Description |
|---|---|
| Type | Capacity |
| Default value | 128M |
| Value range | [0M,+∞)
NoteIn V4.3.x, this parameter was introduced in V4.3.0, and the value range was adjusted from [16M,1G] to [0M,+∞). |
| Modifiable | Yes. You can execute the ALTER SYSTEM SET statement to modify this parameter. |
| Effective upon OBServer node restart | No. The setting takes effect immediately. |
Considerations
This parameter is used to limit the memory usage of the Query Range module. When the memory usage of the Query Range module reaches the upper limit, the system will not extract any ranges. For example, if a complex predicate is matched with an index, and the memory usage of the Query Range module reaches the upper limit when the Query Range module extracts ranges based on the complex predicate, the system will not use the index and instead try to access the primary table.
Example
Set the memory available to the Query Range module to 128 MB.
obclient> ALTER SYSTEM SET range_optimizer_max_mem_size = '128M';