Note
This parameter is introduced since 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 | INT |
| Default value | 20
NoteThe default value is changed from 70 to 20 since OceanBase Database V4.0.0. |
| Value range | (0, 100) |
| Modifiable | Yes. It can be modified using the ALTER SYSTEM SET statement. |
| Effective upon OBServer node restart | No |
Considerations
To adjust the proportion of MemTable in tenant memory, use the following parameters:
When the usage of MemTable memory in a tenant reaches the percentage limited by the
freeze_trigger_percentageparameter, it will automatically trigger a minor compaction, releasing the occupied memory. The default value of this parameter is 20, indicating that a minor compaction will be triggered when MemStore usage exceeds 20%.When there is insufficient memory, you can increase the value of
memstore_limit_percentageand decrease the value offreeze_trigger_percentageto achieve temporary expansion and prompt release by minor compaction. Thememstore_limit_percentageparameter is used to control the proportion of memory available for MemStore writes in tenant memory, with a default value of 50, indicating that tenants can use 50% of the total available memory for MemStore.
Examples
obclient> ALTER SYSTEM SET freeze_trigger_percentage=20;