Note
For V4.2.0, this parameter is available starting with V4.2.0.
Description
storage_meta_cache_priority specifies the priority of the storage Meta Cache in the kvcache.
Privilege requirements
Query the parameter
The
systenant and all user tenants can query this parameter by using theSHOW PARAMETERSstatement or theGV$OB_PARAMETERSview.Modify the parameter
Only the
systenant can modify this parameter. User tenants cannot modify this parameter.
Attributes
| Attribute | Description |
|---|---|
| Type | Int |
| Default value | 10 |
| Value range | [1, +∞) |
| 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
OceanBase Database abstracts Table Store, SSTable, and other metadata into storage Meta and stores it in the kvcache. When the Meta Cache usage is low or frequently misses, you can adjust its priority based on the workload characteristics to improve the efficiency and flexibility of the limited kvcache memory resources.
In the kvcache, a higher priority value indicates a higher priority and a lower likelihood of being evicted. The following are the priority configurations for existing cache types:
tablet_ls_cache_priority, default value is 1000, value range is [1, +∞).
opt_tab_stat_cache_priority, default value is 1, value range is [1, +∞).
index_block_cache_priority, default value is 10, value range is [1, +∞).
user_block_cache_priority, default value is 1, value range is [1, +∞).
user_row_cache_priority, default value is 1, value range is [1, +∞).
bf_cache_priority, default value is 1, value range is [1, +∞).
fuse_row_cache_priority, default value is 1, value range is [1, +∞).
Note that the default priority for storage Meta is the same as that for index_block_cache_priority, which is lower than that for tablet_ls_cache_priority.
Examples
Set the priority of the storage Meta Cache in the kvcache to 10.
obclient> ALTER SYSTEM SET storage_meta_cache_priority='10';