【作者】 周晓云；

【导师】 徐钊；

【作者基本信息】 中国矿业大学 ， 通信与信息系统， 2009， 博士

【摘要】 本文研究面向Cluster环境的并行内存数据库的快速事务提交与高效恢复方法,主要包括三个方面的内容:快速事务提交和日志处理、检查点操作、并行数据库的恢复。本文改进单阶段提交协议,通过日志信息的并行写入硬盘,充分利用IO带宽,加快事务的提交,避免更新密集型应用中日志的堆积。传统两阶段锁协议导致读写事务的加锁冲突,降低系统的吞吐量。本文把加锁协议和临时版本管理结合起来,通过版本管理实现无堵塞的读事务,避免了读写事务之间的互相等待。基于多版本管理实现一致检查点,必须付出版本管理的空间开销代价。本文采用元组级别的版本管理和版本共享技术,版本管理的开销大大降低。在内存越来越大的情况下,这些代价是合理的,因为系统事务处理能力和检查点操作效率得到了较大提高。本文提出基于数据分区的并行恢复算法,实现了恢复过程的系统可用性。恢复过程中,各个站点的恢复工作是相互独立的,同时利用差分日志的特点,实现了数据分区之间,日志之间、数据和日志之间的并行处理,加快了恢复过程,减少了站点恢复的总时间。本文使用J-SIM软件包建模进行仿真实验,验证了所提方案的可行性和效率。结果显示:(1)由于使用快速提交技术和并行日志写入,事务响应时间从50ms降低到21ms;(2)使用并行恢复算法,站点失败的恢复时间从65 s降低到28秒;(3)查询事务的吞吐量比模糊检查点高67%左右,而更新事务的吞吐量比模糊检查点高7.8%左右; (4)在80%更新事务的密集场景中,版本管理的空间开销在11%左右。(5)实验测试的恢复过程中的4个(1/4)时间段,系统平均吞吐量分别为90.2Ktps、98.3Ktps、104.5Ktps、107.7Ktps,事务的平均响应时间分别为273ms、32.3ms、9.2ms、5.32ms。该论文有图49幅,表5个,参考文献121篇。更多还原

【Abstract】 The dissertation focuses on fast committing protocol and higly efficient recovery schems for parallel main memory database on clusters, including: fast transaction committing protocol and logging, checkpointing, and recovery of the parallel main memory database.The dissertation has enhanced traditional one phase committing protocol, and propose using parallel log writing to fully utilize the IO bandwidth to accelerate transaction committing, thus avoided log accumulation in update intensive applications. Traditional two phase locking leads to lock conficts between read only transations and update transactions, which lowers down system throughput. A novel transaction schedule protocol is proposed in this dissertation, transient versioning is combined with locking to support non blocking reading, and avoid conflicts between reader and writers.The consitent checkpointing is implemented on multi versiong, thus space overhead is necessary. Since multi versioning is done on tuple level, and version sharing is used, the overhead is reduced. At present, the capacity of main memory is getting larger and larger, the cost is reasonable, because the efficiency of transaction processing and checkpointing is improved.A partition based parallel recovery algorithm is proposed to provide system availability during recovery. During recovery, recovery of individual sites is independent, parallelism of three types, namely parallelism between partition, parallelism between log disks, and parallelism between data and log, are exploited to speedup recovery, the total recovery time is cut down.The author has used the J-SIM software package to build a simulation system and conducted a seria of experiments, the feasibility and efficiency of the scheme proposed in this dissertation are verified. Experiment results show that: (1) Transaction response time is cut down owing to parallel log writing, from 50ms to 21 ms when log disk number is 8. (2) Total recovery time of the failure site is reduced from 65s to 28s. (3) The scheme achives higher performance than fuzzy checkpointing when the system is performing checkpointing. Query throughput of the scheme improves by about 67 percent over fuzzy checkpointing, and update transaction throughput improves by about 7.8 percent over fuzzy checkpointing. (4) The space overhead is around 11 percent in update intensive senarios, the overhead is acceptable. (5) The final experiment is conducted to measure system throughput and transaction response times during recovery.during four quarters of the recovery, system throughputs are 90.2Ktps、98.3Ktps、104.5Ktps、107.7Ktps, and avarage transaction response time are 273ms、32.3ms、9.2ms、5.32ms respectively.Experimnets results have verified the effetiveness and efficiency of the proposed scheme.The dissertation includes 49 digrams, and 5 tables, and refers to 121 papers.更多还原