Deadlock Prevention Deadlock prevention 是一种事前行为,采用这种方案的 DBMS 无需维护 waits-for graph,也不需要实现 detection 算法,而是在事务尝试获取其它事务持有的锁时直接决定是否需要将其中一个事务中止。 通常prevention 会按照事务的年龄来赋予优先级(加时间戳),事务的时间戳越老,优先级越高。有两种 preve...
dead- lock probabilityIndex Terms: Concurrency controllock conflict probabilitylock contentionmodeling and simulationperformance analysisqueueing network modelstwo-phase lockingvariability in transaction sizeThe performance of transaction processing systems with two-phase locking (2PL) can be degraded by ...
阶段一:Growing:向lock manager获取锁。lock manager决定是否授予lock 阶段二:Shrinking:当一个transaction归还了第一个lock,那么它就进入了Shrinking阶段,它只能够去release lock,而不能够去acquire lock 前后两句话没有关系吧? DeadLock Handling 有两种处理2PL中的deadlock deadlock detection 通过wait-for graph检测d...
The Sufficiency Condition of the Two-Phase Locking without Deadlock 一个两段加锁不死锁的充分条件 www.ilib.cn 4. Multiversion two-phase locking concurrency control protocol in parallel real-time database systems 并行实时数据库系统多版本两阶段封锁并发控制协议 www.ilib.cn 5. Multi-version two-phase...
Two-Phase Locking 2PL 是一种并发控制协议,它帮助数据库在运行过程中决定某个事务是否可以访问某条数据,并且 2PL 的正常工作并不需要提前知道所有事务的执行内容,仅仅依靠已知的信息即可。 2PL,顾名思义,有两个阶段:growing 和 shrinking: 在growing 阶段中,事务可以按需获取某条数据的锁,lock manager 决定同意...
We have analyzed the behavior of a new deadlock-free two-phase locking mechanism, called Cautious Waiting, and have compared its performance with other well-known mechanisms. The mechanism is conceptually quite simple; therefore it is not likely to be difficult to implement. We show that this ...
In this paper we perform a systematic study of the consequences of allowing lock conversions in non-two-phase locking protocols, and show how this leads to increased concurrency and affects deadlock-freedom. The non-two-phase protocols that we study are the very general guard protocols defined ...
APPARATUS AND METHOD FOR SETTING AND RELEASING EXPANDED TWO-STEP LOCK WITH REFERENCE TO PRIOR SEQUENCE OF REAL-TIME TRANSACTION and method transaction with reference to the two-phase locking of the expansion of previous sequence handled in real time while being arranged to enhance... DY Heo,MJ ...
8.2The Two-Phase Commit Protocol Assumptions The protocol makes the following assumptions about each transaction T: 1. Transaction T accesses resources from time to time. If it experiences a serious error at any time, such as adeadlockor illegal operation, it issues an abort operation. If it ...
deadlock danced cultivated crushed creep creativity cousins counseling costume corrected coordinate cooperatives convertible conversations controller contributes container consultation constituents conservatism consecutive conscientious conrad conjugate congressmen confronting conform concord conceivably comrades compositions ...