Collection Contents Index Locking conflicts Particular concurrency issues pdf/chap15.pdf

User's Guide
   PART 2. Relational Database Concepts
     CHAPTER 15. Using Transactions and Locks       

Savepoints within transactions


Adaptive Server Anywhere supports savepoints within a transaction.

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.

Naming and nesting savepoints 

Savepoints can be named and they can be nested. By using named, nested savepoints, you can have many active savepoints within a transaction. Changes between a SAVEPOINT and a RELEASE SAVEPOINT can still 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 make use of the rollback log. They cannot be used in bulk operations mode. There is very little additional overhead in using savepoints.


Collection Contents Index Locking conflicts Particular concurrency issues pdf/chap15.pdf