ITR/SY Collaborative Research: A Unified Relational Approach to Grid Information Services

运行在分布式计算环境（如Computational Grid）中的应用程序必须适应可用的硬件和软件资源。这需要关于网格资源属性的信息，如主机、网络交换机、链接和路径、软件库和系统、用户和组织权限、软件服务、事件通道和字典等等。应用程序运行所需的信息、信息的值（信息更改的速度）和信息的新鲜度（必须以多快的速度将更新推送到应用程序）可能会有很大的不同。这些属性对资源信息服务提出了重要的要求，这些要求在目录服务的一般领域也越来越普遍。网格论坛，一个全球网格计算的国际标准组织，正在开发表示和查询这些信息的标准。这些不断发展的标准有很多优秀之处，但是在这些系统中执行许多形式的非常理想的查询将是困难的或昂贵的。特别是，动态信息需要非常高的更新率，而基于ldap的实现不支持这种更新率。这个项目将通过一个被提议的（暂时命名的）网格资源信息服务（GRIS）来解决这些问题，GRIS是网格信息服务的统一关系方法。研究将从关系数据库系统的完整ACID（原子性/一致性/隔离性/持久性）功能开始，并“向下构建”一个实用的资源信息系统，该系统仍然提供RDBMS的大部分优点。这样的系统将为所有类型的网格资源信息提供一个单一的高度灵活的查询模型和语言，无论它们是多么动态。这项研究最终将以基于商品数据库系统和SQL语言的可扩展实现而告终，包括针对非SQL用户的“罐装查询”。该项目将利用现有网格信息服务的日志更新和查询来评估新系统和技术，并将结果与Globus MDS2等分层系统进行比较。为了便于比较，该项目将从与用户、工具开发人员和网格论坛成员的讨论中生成一组基准查询，并将量化这些查询的限制。

An application running in a distributed computing environment such as the Computational Grid must adapt to the available hardware and software resources. This requires information about the properties of Grid resources such as hosts, network switches, links and paths, software libraries and systems, user and organization rights, software services, event channels and dictionaries, and more. The information needed for an application to run, the values of the information (how fast the information changes) and the freshness of the information (how fast updates must be pushed to the application) can vary dramatically. These attributes place significant demands on the resource information service, demands that are arising with increasing prevalence in the general area of directory services as well. The Grid Forum, an international standards body for world-wide Grid computing, is developing standards for representing and querying this information. There is much that is excellent about these evolving standards, but there are many forms of highly desirable queries that will be difficult or expensive to perform in these systems. In particular, dynamic information will require very high update rates not supported by LDAP-based implementations.This project will address these concerns through a proposed (and tentatively named) Grid Resource Information Service (GRIS), a unified relational approach to grid information services. The research will start with the full ACID (Atomicity/Consistency/Isolation/Durability) functionality of a relational database system and "build down" to a practical resource information system that still provides most of the benefits of the RDBMS. Such a system will provide a single highly flexible query model and language for all types of Grid resource information, no matter how dynamic. The research will culminate in an extensible implementation based on commodity database systems and the SQL language, including "canned queries" for non-SQL users. The project will evaluate the new system and techniques using logged updates and queries from an existing Grid information service, and comparing results with a hierarchical system such as Globus MDS2. To facilitate comparisons, the project will produce a set of benchmark queries from discussions with users, tool developers, and Grid Forum members, and will quantify the limits of these queries.