Lock Inheritance in Nested

The exibility of nested transactions is generally provided at the expenses of a more complex locking mechanism which must deal with expensive lock inheritance. In this paper, we give a solution for eecient lock inheritance. Our solution does not change the original nested transaction model but does revisit its locking rules using set-oriented semantics. This allows us to trade the cost of lock propagation at sub-transaction commit for a potentially more complex connict detection. Then we propose an eecient lock implementation which maintain the overhead of lock requests comparable to the traditional overhead in at transactions. We conducted a number of comparative measurements in order to evaluate our trade-oo. Our benchmarks show a cut oo from 10% to 40% of the global time spent in lock operations, including lock requests and commits.