Note
For V4.4.1, this parameter is available starting with V4.4.1.
Description
external_table_disk_cache_max_percentage specifies the maximum proportion of the disk cache space for external tables to the datafile_size 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 evicts the excess disk cache until the requirement is met. When the value of this parameter is set to 0, the system does not use the disk cache for external table data.
Examples
Set the maximum proportion of the disk cache space for external tables to 60% of the datafile_size.
obclient> ALTER SYSTEM SET external_table_disk_cache_max_percentage = 60;