transaction_read_only

Description

transaction_read_only specifies whether to allow only read-only transactions.

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-compatible mode) or the information_schema.GLOBAL_VARIABLES view (MySQL-compatible mode) to view 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-compatible mode) or the information_schema.SESSION_VARIABLES view (MySQL-compatible mode) to view 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

Usage

When transaction_read_only is set to True, DML statements cannot be executed.

Examples

Allow non-read-only transactions.

• Session level

  obclient> SET transaction_read_only = False;
  

• Global level

  obclient> SET GLOBAL transaction_read_only = False;