The past few years have seen a dramatic increase in the business use of centralized multi-user microcomputer DBMSS without a concomitant attention to the concurrency control mechanisms employed by those DBMSS to ensure the integrity of the data they manage. This paper examines the state-of-the ...
The DBMS contains a centralized lock manager to grants/denies lock requests. (也就是说事务不直接尝试获取锁,而是向Lock Manager发起请求。) For example, if Transaction T1 is reading data from resource A, then it needs to make sure no other transaction is modifying resource A at the same time....
Incentralized locking, there is a single lock table for the entiredistributed database. This lock table is placed, at one of the sites, under the control of a single lock manager. The lock manager is responsible for setting and releasing locks on behalf of transactions. Since all locks are...
Concurrency control by pre-ordering entities in databases with multi-versioned entities This paper presents a protocol for improving concurrency and preserving consistency in databases with multi-versioned entities: the database could be either centralized or distributed and may or may not have data ...
6.1 DBMS Bottlenecks 6.2 Multi-core vs Multi-Node Systems 本文是14年的一篇前瞻性研究,主要是分析OLTP内存数据库的并发控制方案在many-core(dozens or even hundreds of cores on a single chip)机器下的可拓展性。使用模拟器在千核环境下实验表明,文中实现的7种并发控制方案都因为不同原因无法拓展。其中核心的...
Tuples:As shown in Fig. 1, each physical version containsfour meta-data fieldsin its header that the DBMS uses to coordinate the execution of concurrent transactions (some of the concurrency control protocols discussed in the next section include additional fields). ...
control两层和三层数据库体系结构two-tier/three-tier 数据挖掘data mining数据库管理员DBA database administrator表table关系relation元组tuple空值null value数据库模式database schema数据库实例database instance关系模式relation schema关系实例relation instance码keys超码super key候选码candidate key主码primary key外码...
Majority of the research in multilevel secure database management systems (MLS/DBMS) focuses primarily on centralized database systems. However, with the demand for higher performance and higher availability, database systems have moved from centralized to distributed architectures, and the research in...
Concurrency controlMajority of the research in multilevel secure database management systems (MLS/DBMS) focuses primarily on centralized database systems. However, with the demand for higher performance and higher availability, database systems have moved from centralized to distributed architectures, and...
The paper describes an adaptation of the 'rax' protocol for concurrency control in distributed multiservice telecommunication systems. This adaptation has been developed on a prototype distributed database management system (DBMS) implemented at CNET on a version of the Sabrina centralized DBMS. The ...