tailieunhanh - Database Architecture Optimized for the new Bottleneck: Memory Access

The Greenplum Database parallel query optimizer (Figure 6) is responsible for converting SQL or MapReduce into a physical execution plan. It does this by using a cost-based optimization algorithm to evaluate a vast number of potential plans and select the one that it believes will lead to the most efficient query execution. Unlike a traditional query optimizer, Greenplum’s optimizer takes a global view of execution across the cluster, and factors in the cost of moving data between nodes in any candidate plan. The benefit of this “global” query planning approach is that it can use global knowledge and statistical estimates. | Database Architecture Optimized for the new Bottleneck Memory Access Peter Boncz Data Distilleries . Amsterdam The Netherlands Stefan Manegold Martin L. Kersten CWI Amsterdam The Netherlands @ 1 Introduction Abstract In the past decade advances in speed of commodity CPUs have far out-paced advances in memory latency. Main-memory access is therefore increasingly a performance bottleneck for many computer applications including database systems. In this article we use a simple scan test to show the severe impact of this bottleneck. The insights gained are translated into guidelines for database architecture in terms of both data structures and algorithms. We discuss how vertically fragmented data structures optimize cache performance on sequential data access. We then focus on equi-join typically a random-access operation and introduce radix algorithms for partitioned hash-join. The performance of these algorithms is quantified using a detailed analytical model that incorporates memory access cost. Experiments that validate this model were performed on the Monet database system. We obtained exact statistics on events like TLB misses L1 and L2 cache misses by using hardware performance counters found in modern CPUs. Using our cost model we show how the carefully tuned memory access pattern of our radix algorithms make them perform well which is confirmed by experimental results. This work was carried out when the author was at the University of Amsterdam supported by SION grant 612-23-431 Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage the VLDB copyright notice and the title of the publication and its date appear and notice is given that copying is by permission of the Very Large Data Base Endowment. To copy otherwise or to republish requires a fee and or special permission from the Endowment. Proceedings of the .

• Cơ sở dữ liệu
• Key Areas
• Focus and Investments
• Regionalization
• Expanding Core Revenue
• Membership and Sponsorship
• Mission Integral
• Sustainable development
• The grassroots political system
• Ethnic minority
• Mountainous areas
• Natural resources
• công nghệ thông tin
• tin học
• internet
• computer network
• microsoft office
• computer systems
• Endpoint Security
• includes Symantec
• Overshadow Tablets
• Cloud Computing
• Strong Support
• Software Piracy
• Patient involvement
• healthcare professionals
• individual patients
• Patient centred care
• Key principle
• báo cáo khoa học
• báo cáo sinh học
• công trình nghiên cứu về sinh học
• tài liệu về sinh học
• cách trình bày báo cáo
• Establishment
• Biogeographic Areas
• Distributing Endemic
• Dominican Republic
• Biogeography
• Intertidal Barnacles