## 16.5. SQL Grammar Extension for Autonomous Transactions

Postgres Pro `BEGIN`/`END` transaction statements are extended by optional keyword `AUTONOMOUS`:

        BEGIN [AUTONOMOUS] [TRANSACTION] [isolation-level]
        END [AUTONOMOUS] [TRANSACTION]

Specifying `AUTONOMOUS` keyword in `END TRANSACTION` clause is optional. It is possible to have several nesting levels of autonomous transactions, but top level transaction cannot be autonomous.