Note
For V4.1.0, this parameter is available starting with V4.1.0.
Description
dump_data_dictionary_to_log_interval specifies the interval at which the data dictionary is persisted for a tenant.
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
The
systenant and user tenants can modify this parameter.
Attributes
| Attribute | Description |
|---|---|
| Type | Time |
| Default value | 24H, in seconds by default |
| Value range | (0s, +∞) |
| 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
The data dictionary is only available for user tenants. The data dictionary is persisted to the system log stream (SYS_LS) of a user tenant by using the PALF mechanism. After a user tenant is created, the data dictionary service is automatically enabled and runs on the leader replica of the SYS_LS log stream of the tenant.
When log archiving is enabled, an asynchronous data dictionary generation task is automatically triggered. OceanBase Database supports generating the data dictionary by using the tenant-level parameter dump_data_dictionary_to_log_interval.
Starting from OceanBase Database V4.2.0, you can record the data dictionary generation records by using DBA/CDB views. You can query the CDB_OB_DATA_DICTIONARY_IN_LOG view in the sys tenant or the DBA_OB_DATA_DICTIONARY_IN_LOG view in a user tenant to obtain the dictionary location information.
Examples
Set the data dictionary persistence interval for a tenant to 24H.
obclient> ALTER SYSTEM SET dump_data_dictionary_to_log_interval = '24H';
References
- For more information about log archiving, see Log archiving.