Abstract:

In various fields of science there is an exponential growth of the obtained experimental data. A large number of organizations that carry out surveillance, and their independence, a variety of objects of observation, continuous and rapid improvement of observing techniques leads to the necessity of using heterogeneous, distributed information, accumulated over a long period of observation technologically different tools. It should be noted that different sources may provide closely related information, that is, it is desirable to enable users to work with a range of sources such as a single entity. OGSA-DAI [1] is an extension of OGSA, providing the possibility of including information resources (data bases (DB), collections of data) in OGSA. OGSA-DAI interfaces provide access to heterogeneous data resources and can form the basis for creating a higher level of service - federated database systems in Virtual Organizations. Basic services are OGSA-DAI provides a dynamic formation of Grid Data Services (GDS) by factories GDSF. Information about services is placed in the registry (DAISGR) to find services that meet the specified requirements. Ports implement GDS operations to access the database and retrieve results (GDP), as well as the data transport operation GDT. Based on OGSA-DAI can create a distributed database in which the database grid can perform not only data retrieval operation, but also the intermediate operations compute a global response to the request (grid computing), in accordance with a parallel plan. Databases in science are such that the procedures associated with data analysis, so the answer to a query is in the integrated operations of data retrieval and data analysis programs. In contrast to the procedural level of basic services, OGSA-DAI, requires high-level declarative means by which to specify the tasks over the grid database. Different kinds of approaches to the integration of databases (GAV, LAV [3]) require consideration in the implementation of the basic services of OGSA-DAI. Remains a difficult problem of heterogeneity of the database. The purpose of [2] is to develop a service interface is to implement the DBMS and without making changes (naming, multiple formats, fragmentation, asynchronous delivery of results) in existing relational databases and XML. An open question whether the higher layers of the OGSA-DAI for integrated access to heterogeneous databases and their analysis. The virtual database must support the implementation of distributed and heterogeneous queries to database MS SQL Server, Oracle, Postgres and MySQL. Requests for information from the sample database, as well as the transfer and processing facilities of data streams in a distributed file system to be combined into a single stream. User access to data should be based on standard certificates X509. All these requirements are satisfied by the program complex OGSA-DAI/OGSA-DQP.

Keywords: Access to databases using OGSA-DAI and OGSA-DQP