A savepoint is a marker within a transaction that enables you to roll back part of a transaction, rather than the full transaction. Savepoints are available with the SQLite, PostgreSQL, Oracle, and MySQL (when using the InnoDB storage engine) backends. Other backends provide the savepoint functions, but they’re empty operations – they don’t actually do anything.

Savepoints aren’t especially useful if you are using autocommit, the default behavior of Django. However, once you open a transaction with atomic(), you build up a series of database operations awaiting a commit or rollback. If you issue a rollback, the entire transaction is rolled back. Savepoints provide the ability to perform a fine-grained rollback, rather than the full rollback that would be performed by transaction.rollback().

When the atomic() decorator is nested, it creates a savepoint to allow partial commit or rollback. You’re strongly encouraged to use atomic() rather than the functions described below, but they’re still part of the public API, and there’s no plan to deprecate them.

Each of these functions takes a using argument which should be the name of a database for which the behavior applies. If no using argument is provided then the "default" database is used.

Savepoints are controlled by three functions in django.db.transaction:

Creates a new savepoint. This marks a point in the transaction that is known to be in a “good” state. Returns the savepoint ID (sid).

Releases savepoint sid. The changes performed since the savepoint was created become part of the transaction.

Rolls back the transaction to savepoint sid.

These functions do nothing if savepoints aren’t supported or if the database is in autocommit mode.

In addition, there’s a utility function:

Resets the counter used to generate unique savepoint IDs.

The following example demonstrates the use of savepoints:

Savepoints may be used to recover from a database error by performing a partial rollback. If you’re doing this inside an atomic() block, the entire block will still be rolled back, because it doesn’t know you’ve handled the situation at a lower level! To prevent this, you can control the rollback behavior with the following functions.

Setting the rollback flag to True forces a rollback when exiting the innermost atomic block. This may be useful to trigger a rollback without raising an exception.

Setting it to False prevents such a rollback. Before doing that, make sure you’ve rolled back the transaction to a known-good savepoint within the current atomic block! Otherwise you’re breaking atomicity and data corruption may occur.