ob_table_access_policy

Description

The ob_table_access_policy variable specifies the storage format that the optimizer prefers when generating plans for base tables.

Privilege requirements

• Query variables

  • Global level

    sys tenants 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 tenants 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 tenants can directly modify the values of global system variables.

    • MySQL user tenants must have the SUPER or ALTER SYSTEM privilege to modify the values of global system variables.

    • Oracle user tenants must have the ALTER SYSTEM privilege to modify the values of global system variables.

  • Session level

    sys tenants and all user tenants can directly modify the values of session system variables.

Attributes

Examples

Configure the optimizer to prefer columnstore tables when generating plans for base tables.

• Session level

  obclient> SET ob_table_access_policy='COLUMN_STORE';
  

• Global level

  obclient> SET GLOBAL ob_table_access_policy='COLUMN_STORE';