transaction_isolation

Description

transaction_isolation is used to set the transaction isolation level. It works the same as the system variable tx_isolation. Setting either one is sufficient.

Privilege requirements

• Query variables

  • Global level

    The sys tenant and all user tenants can execute the SHOW VARIABLES statement or query the SYS.TENANT_VIRTUAL_GLOBAL_VARIABLE view (in Oracle-compatible mode) or the information_schema.GLOBAL_VARIABLES view (in MySQL-compatible mode) to query the value of a global system variable.

  • Session level

    The sys tenant and all user tenants can execute the SHOW VARIABLES statement or query the SYS.TENANT_VIRTUAL_SESSION_VARIABLE view (in Oracle-compatible mode) or the information_schema.SESSION_VARIABLES view (in MySQL-compatible mode) to query the value of a session variable.

• Modify variables

  • Global level

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

    • MySQL-compatible tenants must have the SUPER or ALTER SYSTEM privilege to modify the value of a global system variable.

    • Oracle-compatible tenants must have the ALTER SYSTEM privilege to modify the value of a global system variable.

  • Session variables

    The sys tenant and all user tenants can directly modify the value of a session system variable in their respective tenant.

Attributes

Examples

Set the 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 transaction isolation levels, see Overview of transaction isolation levels.