Note
This parameter was introduced in OceanBase Database V1.4.
Description
memstore_limit_percentage specifies the percentage of the memory that can be occupied by MemStores to the total available memory of a tenant.
Attributes
| Attribute | Description |
|---|---|
| Type | Integer |
| Default value | 0: specifies to automatically adapt the value.
NoteThe default value of this parameter has been changed from |
| Value range | [0, 100)
NoteThe value range of this parameter has been changed from (0, 100) to [0, 100) since OceanBase Database V4.3.0. |
| Modifiable | Yes. You can use the ALTER SYSTEM SET statement to modify the parameter. |
| Effective upon OBServer node restart | No |
Considerations
The
memstore_limit_percentageparameter is used to calculate the value ofmemstore_limitby using the following formula:memstore_limit_percentage=memstore_limit/memory_sizeIn the formula,
memory_sizeindicates the total available memory of the tenant and is specified during tenant creation. For more information aboutmemstore_limit, see memory_limit.OceanBase Database V4.3.0 and later allow you to use the tenant-level hidden parameter
_memstore_limit_percentageto specify the percentage of the memory that can be occupied by MemStores to the total available memory of a tenant. Except for the effective scope, its feature and default value are the same as those of the cluster-level parametermemstore_limit_percentage. When you specify the two parameters, take note of the following considerations:
- If you specify a value other than the default value only for
_memstore_limit_percentageormemstore_limit_percentage, the specified value prevails. - If you specify values, other than the default values, for both the tenant-level hidden parameter
_memstore_limit_percentageand the cluster-level parametermemstore_limit_percentage, the value of_memstore_limit_percentageprevails. - If neither parameter is specified or the default values are used for both parameters, the system complies with the following rules:
- For a tenant with 8 GB of memory or less, the percentage of memory that can be occupied by MemStores is 40%.
- For a tenant with more than 8 GB of memory, the percentage of memory that can be occupied by MemStores is 50%.
Example
obclient> ALTER SYSTEM SET memstore_limit_percentage = 60;