ABORT rolls back the current transaction and causes all the updates made by the transaction to be discarded. This command is identical in behavior to the standard SQL command ROLLBACK, and is present only for historical reasons.
Use COMMIT to successfully terminate a transaction.
Issuing ABORT when not inside a transaction does no harm, but it will provoke a warning message.
This command is a PostgreSQL extension present for historical reasons. ROLLBACK is the equivalent standard SQL command.