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A Design and Implementation of Savepoints and Partial Rollbacks Considering Transaction Isolation Levels of SQL2
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Sun Hwan Kim,
Mi Suk Jung,
Jun Hyun Park, and
Young Chul Park
View Paper (PDF)
Return to Session 6A: Transaction Management
A Design and Implementation of Savepoints and Partial Rollbacks Considering
Transaction Isolation Levels of SQL2
A partial rollback of a transaction restores the
state of the transaction and the database to the state in which they have been
right after the savepoint to be rolled back has been established. Contributions
of this paper toward the correctness of savepoints and partial rollbacks are
the followings.
First, a savepoint sequence number is assigned to each
savepoint. According to that, without generating any savepoint log record upon
establishing savepoints, all the valid savepoints of a transaction can have
different savepoint sequence numbers and the order of establishment of each
valid savepoint can be discriminated efficiently.
Second, the lock request
entries of the manual duration are not deleted from the lock table as far as
some savepoints which are established after the locks are requested but before the
locks are released are valid. That guarantees the correctness of savepoints and
partial rollbacks under the circumstances of supporting the four transaction
isolation levels of SQL2.
Third, the concept of the mini-savepoint that
preserves the atomicity of update operations of the SQL level is extended and
adopted to triggers and stored procedures. According to that, the atomicity of
triggers and stored procedures is supported and the scope of savepoint names is
restricted to the internal of the corresponding triggers or stored procedures.
Keywords:
savepoint, partial rollback, transaction isolation levels, trigger, and stored
procedure.
Copyright(C) 2000 ACM
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