A mechanism is provided for generating statistical information for query optimization in a data processing system. The mechanism comprises a first database engine maintaining a current first dataset currently being stored, a second database engine maintaining a second dataset. The second dataset is ...
In a distributed database system, processing a query comprises of optimization at both the global and the local level. The query enters the database system at the client or controlling site. Here, the user is validated, the query is checked, translated, and optimized at a global level....
Relational Algebra Query Optimization in Distributed DBMS - Learn about relational algebra query optimization techniques in distributed database management systems to enhance performance and efficiency.
Similarity-awareQueryProcessingandOptimization * YasinN.Silva Supervisedby:WalidG.Aref DepartmentofComputerScience,PurdueUniversity {ysilva,aref}@cs.purdue.edu ABSTRACT Manyapplicationscenarios,e.g.,marketinganalysis,sensor networks,andmedicalandbiologicalapplications,requireorcan ...
an optimization problem where, given a workload of queries, we select a stratified random sample of the original data such that the error in answering the workload queries using the sample is minimized. A key novelty of our approach is that we can tailor the choice of samples to be robust...
Database | 浅谈Query Optimization (1),综述由于SQL是声明式语言(declarative),用户只告诉了DBMS想要获取什么,但没有指出如何计算。因此,DBMS需要将SQL语句转换成可执行的查询计划(QueryPlan)。但是对同样的数据可以有多种查询方案,性能也差距很大,查询优化器(QueryO
关键词:Query Optimization, Cost Model, MPP, Parallel Processing 前言 大数据带来了对查询优化的新兴兴趣,因为一种新型的数据管理系统在可扩展性、可用性和处理能力方面推动了前所未有的突破(例如,[9,18,20,21]),这使得数百TB甚至PB级别的大型数据集可以通过SQL或类似SQL的接口轻松进行分析。优化器的好坏差异一直...
Cloud computing is having a major impact on data management, with a proliferation of new, scalable data management solutions such as distributed file and object storage, NoSQL databases and big data processing frameworks. This also leads to a wide diversification of DBMS interfaces and the loss of...
Ward, “A Compositional Approach for the Design of a Parallel Query Processing Language”, Int. Conf. on Parallel Architectures and Language Europe, Paris, France, June 1992. Google Scholar B. Dageville, P. Casadessus, P. Borla-Salamet, “The Impact of the KSR1 AllCache Architecture on ...
mpp query optimization 一Query 1 Parsing 代码语言:javascript 代码运行次数:0 运行 AI代码解释 ParserQueryparser(end,settings.enable_debug_queries);ASTPtr ast;//把Query转化为抽象语法树ast=parseQuery(parser,begin,end,"",max_query_size); ASTPtrtryParseQuery(){//Token为lexer词法分析后的基本单位,...