| 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...
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