Note
This parameter was introduced in OceanBase Database V1.4.
Description
freeze_trigger_percentage specifies the threshold of memory used by tenants for triggering a global freeze.
Attributes
| Attribute | Description |
|---|---|
| Type | Integer |
| Default value | 20
NoteThe default value has been changed from |
| Value range | (0, 100) |
| Modifiable | Yes. You can use the ALTER SYSTEM SET statement to modify the parameter. |
| Effective upon OBServer node restart | No |
Considerations
You can specify the following parameters to adjust the percentage of MemTables in the memory for the tenant:
When the memory space of the tenant occupied by MemTables reaches the threshold specified by the
freeze_trigger_percentageparameter, the system automatically triggers a minor compaction and then releases the occupied memory space. The default value of this parameter is20, which indicates that a minor compaction is triggered when the MemStore usage exceeds 20%.When the memory is insufficient, you can increase the value of the
memstore_limit_percentageparameter and lower the value of thefreeze_trigger_percentageparameter to temporarily scale up the memory and promptly release the memory space. Thememstore_limit_percentageparameter specifies the percentage of memory available for MemStore writes. The default value is50, which indicates that the MemStore memory accounts for 50% of the total memory of the tenant.
Example
obclient> ALTER SYSTEM SET freeze_trigger_percentage=20;