【作者】 寇玮华；

【导师】 徐扬；

【作者基本信息】 西南交通大学 ， 交通信息工程及控制， 2004， 博士

【摘要】 在分布式数据库领域，分布式数据更新是极其重要的研究课题，因为数据更新操作必须满足数据库的完整性、一致性、可靠性和稳定性要求。针对分布式数据库的要求，分布式数据更新有强一致性和弱一致性之分，强一致性的数据更新是通过分布式事务的协议进行，这个协议必须满足ACID特性；弱一致性主要体现在数据副本复制上。 借鉴分布式数据库领域中众多专家、学者关于分布式数据更新的相关研究工作，取得了以下研究成果： 一 提出并构造了满足强一致性及ACID特性的P2L2PC协议 1．分布式数据库的传统连接结构具有各自优点的同时，它们有其无法克服的问题，为了解决这些问题，应在链路补偿方面作一定研究，使链路生成和形成多元化，为分布式数据更新提供更完善的连接结构，基于此目的建立了并行分层式链路。并行分层式链路是在一个连接结构中，具有链路分层的同时又有补偿的并行链路，最终目的是完善、优化地执行分布式数据更新。 2．目前已经提出许多分布式数据库提交协议，尽管这些协议都能保证分布式事务ACID特性，但基本采用的是投票法的“一票一次性否决”规则。本文采用投票法“一票多次性否决”规则，提出并构造了P2L2PC协议，即数据更新在并行分层式链路基础上，只有在一个参与者的一个子事务的所有消息是提议撤消情况下，协调者才能确认该参与者是建议撤消。 3．按照分布式事务原则的要求，对P2L2PC协议是否满足各个准确性准则进行了证明。通过证明可知P2L2PC协议在分布式数据更新时很好地保证了分布式事务原子性，即维护了数据库的一致性。 4．通过记录日志次数、报文交换数量和事务失败率三个方面将2L2PC协议和其它协议进行了性能评价和比较。P2L2PC协议通过适当提高日志操作次数和报文发送次数来降低协议执行的失败率，表明P2L2PC协议有其特定的优点，尤其是P2L2PC协议较高的成功率，使分布式数据更新事务的成功得到保证。 5．对分布式数据更新时可能发生的故障进行了分类分析，并针对P2L2PC协议设计了故障恢复协议和事务终结协议。故障的发生是破坏数据库完整性和一致性的主要原因，通过对分布式数据库系统故障的模糊性界定，使第日页西南交通大学博士研究生学位论文PZLZPC协议在故障恢复时，具有较高的可靠性;通过对故障发生在不同阶段的终结请求分析，设计了PZLZPC协议的终结协议，从终结分析和终结协议的设计可以看出，PZLZPC协议消除分布式事务被挂起现象，即尽可能不让事务阻断发生。二弱一致性的副本更新问题研究 1.基于并行分层式链路对传统的对等复制进行了改进，提出了优先级约束的衍生对等复制策略，同时推断出衍生对等复制的可行性链路;结合对等复制和优先级约束原则设计了优先级约束衍生对等复制算法，为副本复制的并发控制奠定了一定基础。 2.对分布式数据库系统发展过程中出现的多分割副本问题进行了系统的分析，同时对多分割副本传播复制提出了三种策略:单次传播复制策略、二次传播吞吐复制策略和并行二次传播吞吐复制策略。三种策略的基本思想是将多分割副本分解再吞吐传播，并还原复制，主要解决副本数据不重复传播问题、未修改数据不进行传播问题及并行链路中多分割副本复制问题。三针对pZLZpc协议及副本复制问题进行并发控制研究 1.基于时效期对PZLZPC协议的并发控制问题进行了分析，并建立了尸ZLZPC协议的时效锁并发控制方式。 2.针对对等复制过程中并发情况提出了中断策略和优先级准封锁策略，同时对多分割副本复制过程中的并发控制问题进行了分类分析，并提出了多分割副本复制的并发控制算法。四结合快速发展的分布式应用技术，对本文的理论研究内容进行了技术实现方面的可行性设计，从而提出了分布式数据库接力访问模型。 1.分布式数据库接力访问模型的核心思想是将多层体系结构的分布式应用技术应用于分布式数据库访问上。 2.分布式数据库接力访问模型功能特点是将请求异地数据和异地数据请求都以消息机制进行推送，解决在访问分布式数据库情况下网络开销过大、数据库互连复杂、数据更新时保证一致性困难等问题。关键词:ZPC协议;PZLZPC协议;副本复制; 分布式数据更新;分布式数据库系统更多还原

【Abstract】 In the field of DDBS(distributed database system), distributed data updating is a very important researchful problem, because data updating must fulfil integrality, coherence, reliability and stability of the database. From the requiring of the DDBS, distributed data updating is divided into strong coherence and weak coherence. In strong coherence, data updating is done by the protocol of distributed transaction, this protocol must fulfil ACID. Weak coherence aim at copy replication. Use for reference the many research of other expert and scholar, the following research results are achieved. 1. P2L2PC Protocol Fulfilling Strong Coherence and ACID is Researched(a) The traditional link structure of DDBS has itself strong characteristic, but also it has incontestable shortcoming, so should to do research in redeeming link, to provid perfect link for distributed data updating, base on this purpose to building Parallel-Layered-Link.(b) Now, many DDBS protocol have been researched, but these protocol adopted basically "one vote one-off veto"of voting means. P2L2PC protocol adopt "one vote time after time veto" rule. Distributed data updating is done by Parallel-Layered-Link,only when all message of one participator subtransaction report abort, coordinator confirm that this participator request abort.(c) By proving, when distributed data is updated, P2L2PC protocol assure primely the atomic of distributed transaction, also assure the coherence of database in time.(d) From recording log count, commutative message amount, transaction aborted ratio, P2L2PC protocol is compared with other protocol. P2L2PC protocol reduce aborted ratio by enhancing moderately log manipulative count and message sending count, this explain that preferable successful ratio of P2L2PC protocol make a good ensuring in distributed data updating.(e) Possible went wrong is-analyzed classifyly when distributed data updating, so failure resumptive protocol and terminative protocol are devised to P2L2PC protocol. The occurring of failure is most cause destroying the integrality and coherence of DDBS, by differentiating absolutely the failure, to make P2L2PCprotocol has better reliability in revertting failure. By analyzing terminative request in different failure phase, the terminative protocol is devised. It is know that P2L2PC protocol eliminates the interdictted transaction.2. Copy Replication in Weak Coherence(a) Base on Parallel-Layered-Link, to ameliorate traditional peer to peer replication, raise pri restrict derivative peer to peer replication, and deduce feasibility reproductive link, peer to peer replication and pri restrict rule combine to form pri restrict derivative peer to peer replication algorithm.(b) By analyzing detailedly multi-intersected copy, three methods of replication are devised: once spread replication method, twi-spread thruput replication method and parallel twi-spread thruput replication method. Their essential thinking is that multi-intersected copy is disassembled, spread, reverted, and replication, they make that data is spread unrepeatedly, data unamended is not spread, and how to data spread and replicate in parallel link.3. Concurrency Control of P2L2PC and Multi-Intersected Copy Replication(a) Base on time limit, to analyze concurrency control of P2L2PC protocol, and upbuild method of time limit lock concurrency control of P2L2PC protocol.(b) Interruptive method and pre-lock method are put forward, and by analyzing detailedly concurrency control of multi-intersected copy replication, to devise algorithm of concurrency control of multi-intersected copy.4. Combining rapidly developing distributed applied technique, in technicalrealizing, to do feasibility design for theoretic part researched, and thebaton model of distributed database is put forward.The principle and technology of baton model are that distributed application is applied on distributed database. It’s function is that request ecdemic data or ecdemic data request is pushed by messa更多还原