Can-Follow Concurrency Control
ABSTRACT Can-follow concurrency control permits a transaction to read (write) an item write-locked (read-locked) by another transaction with almost no delays. By combining the merits of 2PL and 2V2PL, this approach mitigates the lock contention not only between update and read-only transactions, but also between update and update transactions.
- SourceAvailable from: Alexander Thomasian[show abstract] [hide abstract]
ABSTRACT: Since the appearance of the first papers in mid-70’s formalizing two-phase locking as a means of Concurrency Control (CC) , there have been numerous proposals based on locking, time-stamp ordering, and optimistic CC , , . CC is required to ensure correctness and database integrity when it is updated by several transactions concurrently .12/1999: pages 329-354;
- [show abstract] [hide abstract]
ABSTRACT: this paper, we deal with the problem of atomicity and isolation in the context of processes. We propose a unified model for concurrency control and recovery for processes and show how this model can be implemented in practice, thereby providing a complete framework for developing middleware applications using processesACM Trans. Database Syst. 01/2002; 27:63-116.
Article: Recovery from malicious transactions[show abstract] [hide abstract]
ABSTRACT: Preventive measures sometimes fail to deflect malicious attacks. We adopt an information warfare perspective, which assumes success by the attacker in achieving partial, but not complete, damage. In particular, we work in the database context and consider recovery from malicious but committed transactions. Traditional recovery mechanisms do not address this problem, except for complete rollbacks, which undo the work of benign transactions as well as malicious ones, and compensating transactions, whose utility depends on application semantics. Recovery is complicated by the presence of benign transactions that depend, directly or indirectly, on the malicious transactions. We present algorithms to restore only the damaged part of the database. We identify the information that needs to be maintained for such algorithms. The initial algorithms repair damage to quiescent databases; subsequent algorithms increase availability by allowing new transactions to execute concurrently with the repair process. Also, via a study of benchmarks, we show practical examples of how offline analysis can efficiently provide the necessary data to repair the damage of malicious transactions.IEEE Transactions on Knowledge and Data Engineering 10/2002; · 1.89 Impact Factor