Note
For V4.4.1, this parameter is available starting with V4.4.1.
Description
external_table_disk_cache_max_percentage specifies the maximum percentage of datafile_size that can be used for disk caching of external tables in SN mode.
Notice
This parameter is available only in SN mode.
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
Only the
systenant can modify this parameter. User tenants cannot modify this parameter.
Attributes
| Attribute | Description |
|---|---|
| Type | INT |
| Default value | 50 |
| Value range | [0, 95] |
| 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
When the value of the external_table_disk_cache_max_percentage parameter is reduced, the system automatically frees up disk cache space in the background until the specified percentage is met. If this parameter is set to 0, the system does not use disk caching for external table data.
Examples
Set the maximum percentage of datafile_size that can be used for disk caching of external tables to 60%.
obclient> ALTER SYSTEM SET external_table_disk_cache_max_percentage = 60;