ASA SQL User's Guide
Using Transactions and Isolation Levels
Introduction to transactions
You may identify important states within a transaction and return to them selectively using savepoints to separate groups of related statements.
A SAVEPOINT statement defines an intermediate point during a transaction. You can undo all changes after that point using a ROLLBACK TO SAVEPOINT statement. Once a RELEASE SAVEPOINT statement has been executed or the transaction has ended, you can no longer use the savepoint.
No locks are released by the RELEASE SAVEPOINT or ROLLBACK TO SAVEPOINT commands: locks are released only at the end of a transaction.
Using named, nested savepoints, you can have many active savepoints within a transaction. Changes between a SAVEPOINT and a RELEASE SAVEPOINT can be canceled by rolling back to a previous savepoint or rolling back the transaction itself. Changes within a transaction are not a permanent part of the database until the transaction is committed. All savepoints are released when a transaction ends.
Savepoints cannot be used in bulk operations mode. There is very little additional overhead in using savepoints.