Partial Rollback: Savepoints
[Transactions, Locking and Logging]

Collaboration diagram for Partial Rollback: Savepoints:

---

Detailed Description

A transaction may perform a partial rollback using savepoints. The transaction populates a savepoint by calling ss_m::save_work, then it may roll back to that point with ss_m::rollback_work. Locks acquired between the save_work and rollback_work are not released.

Classes
class	sm_save_point_t
	A point to which a transaction can roll back. More...
Functions
static rc_t	ss_m::save_work (sm_save_point_t &sp)
	Populate a save point.
static rc_t	ss_m::rollback_work (const sm_save_point_t &sp)
	Roll back to a savepoint.

---

Function Documentation

static rc_t ss_m::save_work

(

sm_save_point_t &

sp

)

[static, inherited]

Populate a save point.

Parameters:

[out]

sp

An sm_save_point_t owned by the caller.

Store in sp the needed information to be able to roll back to this point. For use with rollback_work.

Note:

Only one thread may be attached to a transaction when this is called.

static rc_t ss_m::rollback_work

(

const sm_save_point_t &

sp

)

[static, inherited]

Roll back to a savepoint.

Parameters:

[in]

sp

An sm_save_point_t owned by the caller and populated by save_work.

Undo everything that was done from the time save_work was called on this savepoint.

Note:

Locks are not freed.

Only one thread may be attached to a transaction when this is called.

---