transaction_isolation

Description

transaction_isolation specifies the transaction isolation level. It is identical to the system variable tx_isolation.

Privilege requirements

• Query variables

  • Global level

    The sys tenant and all user tenants can use the SHOW VARIABLES statement or the SYS.TENANT_VIRTUAL_GLOBAL_VARIABLE view (Oracle mode) or the information_schema.GLOBAL_VARIABLES view (MySQL mode) to query the value of Global system variables.

  • Session level

    The sys tenant and all user tenants can use the SHOW VARIABLES statement or the SYS.TENANT_VIRTUAL_SESSION_VARIABLE (Oracle mode) and information_schema.SESSION_VARIABLES (MySQL mode) views to view the values of Session system variables.

• Modify variables

  • Global level

    • The sys tenant can directly modify the values of Global system variables.

    • MySQL user tenants must have the SUPER or ALTER SYSTEM privilege to change the value of Global system variables.

    • For V4.x releases, starting from V4.2.0, an Oracle user tenant must have the ALTER SYSTEM privilege to change the value of global system variables.

  • Session level

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

Attributes

Examples

Set the transaction isolation level of a transaction to READ-COMMITTED.

• Session level

  obclient> SET transaction_isolation = 'READ-COMMITTED';
  

• Global level

  obclient> SET GLOBAL transaction_isolation = 'READ-COMMITTED';
  

References

For more information about the transaction isolation levels, see Overview of transaction isolation levels.