31748919
DB2 Query Parallelism: Staging and Implementation
21401289
Parallelism in Relational Database Management Systems
In order to provide real-time responses to complex queries involving large volumes of data, it has become necessary to exploit parallelism in query processing. This paper addresses the issues and solutions relating to intraquery parallelism in a relational database management system (DBMS). We provide a broad framework for the study of the numerous issues that need to be addressed in supporting parallelism efficiently and flexibly. The alternatives for a parallel architecture system are discussed, followed by the focus on how a query can be parallelized and how that affects load balancing of the different tasks created. The final part of the paper contains information about how the IBM DATABASE 2™ (DB2®) Version 3 product provides support for I/O parallelism to reduce response time for data-intensive queries.
20214518
Extensible Indexing Support in DB2 Universal Database
Publisher Summary Emerging database (DB) applications require the scalable management of a large quantity of complex data, together with traditional business data and flexible querying capabilities for business intelligence. Object-relational databases or universal servers are component database management systems (DBMSs) developed to support applications. They leverage the mature relational database technology that provides scalability, reliability, and recovery. They enable users to introduce application-specific types and methods into a database. These extensibility features can be seen as infrastructure for providing plug-in components that extend the built-in repertoire of database types and functions with support for additional, nonstandard data types. Tables in a database may contain user-defined objects such as geographical shapes, images, and semi-structured or unstructured text documents. This chapter presents a high-level framework of indexing for user-defined types. The framework allows users to concentrate on the semantics of applications and user-defined predicates without being concerned with the low-level details of locking, recovery, buffer management, or balanced search-tree updates. It is tightly integrated with the database engine and enhances the value of underlying access methods, built-in or user-defined, in a database system by supporting indexing on new data types and indexed scans using new predicates.
35134245
Single Table Access Using Multiple Indexes: Optimization, Execution, and Concurrency Control Techniques
Many data base management systems' query optimizers choose at most one index for accessing the records of a table in a given query, even though many indexes may exist on the table. In spite of the fact that there are some systems which use multiple indexes, very little has been published about the concurrency control or query optimization implications (e.g., deciding how many indexes to use) of using multiple indexes. This paper addresses these issues and presents solutions to the associated problems. Techniques are presented for the efficient handling of record ID lists, elimination of some locking, and determination of how many and which indexes to use. The techniques are adaptive in the sense that the execution strategies may be modified at run-time (e.g., not use some indexes which were to have been used), if the assumptions made at optimization-time (e.g., about selectivities) turn out to be wrong. Opportunities for exploiting parallelism are also identified. A subset of our ideas have been implemented in IBM's DB2 V2R2 relational data base management system.
6838561
High Level Indexing of User-Defined Types
206780897
An efficient hybrid join algorithm: a DB2 prototype
A new join method, called hybrid join, is proposed which uses the join-index filtering and the skip sequential prefetch mechanism for efficient data access. With this method, the outer table is sorted on the join column. Then, the outer is joined with the index on the join column of the inner. The inner tuple is represented by its surrogate, equivalent of its physical disk address, which is carried in the index. The partial join result is sorted on the surrogate and then the inner table is accessed sequentially to complete the join result. Local predicate filtering can also be applied before the access of the inner relation through the index AND/ORing. Efficient methods for skip sequential access and prefetching of logically discontiguous leaf pages of B/sup +/-tree indexes are also presented.<<ETX>>
11631224
An Algorithm for Finding Parameter Dependent: Connected Components of Gray Images
In a previous work we have introduced the concept of a parameter-dependent connected component of grayscale images that takes into account both the gray values of the pixels and the di erences of the gray values of the neighboring pixels. This concept is a convenient tool to analyze or understand images at a higher level than the pixel level. In this paper, we describe an algorithm for nding the parameter-dependent components for a given image. We discuss di erent strategies used in the algorithm and analyze their e ects through the experimental results. Since the proposed algorithm is independent of the formation of the images, it can be used for the analysis of many types of images. The experimental results show that for some appropriate values of the parameters, the objects of an image may be represented by its parameter-dependent components reasonably well. Thus, the proposed algorithm provides us with the posibility of analyzing images further at the component level.
6870100
A hybrid cultural ecology: world of warcraft in China
We analyze online gaming as a site of collaboration in a digital-physical hybrid. We ground our analysis in findings from an ethnographic study of the online game World of Warcraft in China. We examine the interplay of collaborative practices across the physical environment of China's Internet cafes and the virtual game space of World of Warcraft. Our findings suggest that it may be fruitful to broaden existing notions of physical-digital hybridity by considering the nuanced interplay between the digital and physical as a multi-dimensional environment or "ecology". We illustrate how socio-economics, government regulations and cultural value systems shaped a hybrid cultural ecology of online gaming in China.
2947494
High Resolution Tracking of Non-Rigid Motion of Densely Sampled 3D Data Using Harmonic Maps
Abstract
We present a novel automatic method for high resolution, non-rigid dense 3D point tracking. High quality dense point clouds of non-rigid geometry moving at video speeds are acquired using a phase-shifting structured light ranging technique. To use such data for the temporal study of subtle motions such as those seen in facial expressions, an efficient non-rigid 3D motion tracking algorithm is needed to establish inter-frame correspondences. The novelty of this paper is the development of an algorithmic framework for 3D tracking that unifies tracking of intensity and geometric features, using harmonic maps with added feature correspondence constraints. While the previous uses of harmonic maps provided only global alignment, the proposed introduction of interior feature constraints allows to track non-rigid deformations accurately as well. The harmonic map between two topological disks is a diffeomorphism with minimal stretching energy and bounded angle distortion. The map is stable, insensitive to resolution changes and is robust to noise. Due to the strong implicit and explicit smoothness constraints imposed by the algorithm and the high-resolution data, the resulting registration/deformation field is smooth, continuous and gives dense one-to-one inter-frame correspondences. Our method is validated through a series of experiments demonstrating its accuracy and efficiency.

32478144
Experience from a real life query optimizer
DB2 is a major relational database system on IBM main frames, it has over six thousand licenses over the world to support a very large number of major applications for customer business, Optimizer in DB2 is a critical component for the query processing, it inherited system R technologies and has been improved in very many aspects from numerous valuable real life experiences on customer applications. The major DB2 optimizer enhancements will be discussed with the backgrounds and examples. A wish list for future enhancements as well as some trend and direction of DB2 optimizer will also be discussed.
122644283
Implementation of a modified Marder-Weitzner method for solving nonlinear eigenvalue problems
Our goal is to propose four versions of modified Marder-Weitzner methods and to present the implementation of the new-type methods with incremental unknowns for solving nonlinear eigenvalue problems. By combining with compact schemes and modified Marder-Weitzner methods, six schemes well suited for the calculation of unstable solutions are obtained. We illustrate the efficiency of the new algorithms by using numerical computations and by comparing them with existing methods for some two-dimensional problems.