SAVEPOINT

`SAVEPOINT`

Creates a savepoint

Syntax

SAVEPOINT sp_name

Table 1. SAVEPOINT Statement Parameter
Parameter	Description
sp_name	Savepoint name.Available only in DSQL

The SAVEPOINT statement creates an SQL-compliant savepoint that acts as a marker in the “stack” of data activities within a transaction.Subsequently, the tasks performed in the “stack” can be undone back to this savepoint, leaving the earlier work and older savepoints untouched.Savepoints are sometimes called “nested transactions”.

If a savepoint already exists with the same name as the name supplied for the new one, the existing savepoint is released, and a new one is created using the supplied name.

To roll changes back to the savepoint, the statement ROLLBACK TO SAVEPOINT is used.

Note

Memory Considerations

The internal mechanism beneath savepoints can consume large amounts of memory, especially if the same rows receive multiple updates in one transaction.When a savepoint is no longer needed, but the transaction still has work to do, a [fblangref50-transacs-releasesp] statement will erase it and thus free the resources.

Sample DSQL session with savepoints

CREATE TABLE TEST (ID INTEGER);
COMMIT;
INSERT INTO TEST VALUES (1);
COMMIT;
INSERT INTO TEST VALUES (2);
SAVEPOINT Y;
DELETE FROM TEST;
SELECT * FROM TEST; -- returns no rows
ROLLBACK TO Y;
SELECT * FROM TEST; -- returns two rows
ROLLBACK;
SELECT * FROM TEST; -- returns one row

`RELEASE SAVEPOINT`

Releases a savepoint

Syntax

RELEASE SAVEPOINT sp_name [ONLY]

Table 1. RELEASE SAVEPOINT Statement Parameter
Parameter	Description
sp_name	Savepoint name.Available only in DSQL

The statement RELEASE SAVEPOINT erases a named savepoint, freeing up all the resources it encompasses.By default, all the savepoints created after the named savepoint are released as well.The qualifier ONLY directs the engine to release only the named savepoint.