Note
This parameter is available since V4.6.0.
Description
default_delta_format specifies the default incremental data storage format when creating a table.
Permissions
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 | String |
| Default value | flat |
| Value range |
|
| 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
You can modify the default_delta_format parameter to specify the default incremental data format for tables without repeatedly specifying the format when creating tables:
flat: This format has a fast write speed and low compression ratio. It is suitable for OLTP scenarios.encoding: This format has a slower write speed and higher compression ratio. It can improve query performance in OLAP scenarios, reduce the storage space for incremental data, and provide better query performance when theMERGE_ENGINEparameter of a table is set todelete_insert. For information about how to set theMERGE_ENGINEparameter of a table, see Specify the update model of a table or Specify the update model of a table.
Examples
Set the incremental data format of tables created in a user tenant to
encoding.obclient> ALTER SYSTEM SET default_delta_format = "encoding";Set the incremental data format of tables created in a user tenant to
flat.obclient> ALTER SYSTEM SET default_delta_format = "flat";