optimizer_features_enable

Description

optimizer_features_enable specifies the OceanBase Database version whose optimizer features are enabled.

Privilege requirements

• Query variables

  • Global level

    sys tenant and all user tenants can execute the SHOW VARIABLES statement or query the SYS.TENANT_VIRTUAL_GLOBAL_VARIABLE view (Oracle mode) or the information_schema.GLOBAL_VARIABLES view (MySQL mode) to obtain the values of global system variables.

  • Session level

    sys tenant and all user tenants can execute the SHOW VARIABLES statement or query the SYS.TENANT_VIRTUAL_SESSION_VARIABLE view (Oracle mode) or the information_schema.SESSION_VARIABLES view (MySQL mode) to obtain the values of session system variables.

• Modify variables

  • Global level

    • sys tenant can directly modify the value of a global system variable.

    • MySQL user tenants need to have the SUPER or ALTER SYSTEM privilege to modify the value of a global system variable.

    • Oracle user tenants need to have the ALTER SYSTEM privilege to modify the value of a global system variable.

  • Session level

    sys tenant and all user tenants can directly modify the value of a session system variable of the current tenant.

Attributes

Examples

Enable the optimizer features of OceanBase Database V4.2.5.4.

• Global level

  obclient> SET GLOBAL optimizer_features_enable='4.2.5.4';
  

• Session level

  obclient> SET optimizer_features_enable='4.2.5.4';