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Chinese Virtual Observatory. OGSA-DAI 简介及其它在 China-VO DAS 系统中的应用. 杨阳 中国虚拟天文台研发团队. outline. OGSA-DAI DAI’s application -China-VO DAS Extendable characteristics -OGSA-DQP software. OGSA-DAI. KEY OGSA: Open Grid Service Architecture DAI: Data Access and Integrate
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Chinese Virtual Observatory OGSA-DAI简介及其它在China-VO DAS系统中的应用 杨阳 中国虚拟天文台研发团队
outline • OGSA-DAI • DAI’s application -China-VO DAS • Extendable characteristics -OGSA-DQP software VO Tutorial @ CAS 2006
OGSA-DAI • KEY OGSA: Open Grid Service Architecture DAI: Data Access and Integrate WSRF: Web Service Resource Framework DAS: Data Access Service VO Tutorial @ CAS 2006
What is OGSA-DAI ? • OGSA-DAI is a middleware to assist with access and integration of data from separate sources via the grid. It allows data resources, such as relational or XML databases, to be exposed on to Grids and to be accessed via web services. VO Tutorial @ CAS 2006
What can OGSA-DAI do ? • Different types of data resources - including relational, XML and files - can be exposed via web services. A number of popular data resource products are supported. • Data within each of these types of resource can be queried and updated. VO Tutorial @ CAS 2006
Data can be transformed (using XSLT), compressed and decompressed (using ZIP and GZIP compression). • Data can be delivered to clients, other OGSA-DAI web services, URLs, FTP servers, GridFTP servers, or files. VO Tutorial @ CAS 2006
Requests to OGSA-DAI web services have a uniform format irrespective of the data resource exposed by the service. (though the actions specified within each request may be data resource-specific). • Information on the data resources exposed by an OGSA-DAI web service and the functionality supported by the service can be accessed by clients. VO Tutorial @ CAS 2006
Architecture VO Tutorial @ CAS 2006
Important concepts • Actions • Activity • Session • Perform document • Response document VO Tutorial @ CAS 2006
Actions VO Tutorial @ CAS 2006
Activity • the operations that a data service resource can perform, including data resource manipulation, data transformation and data delivery operations VO Tutorial @ CAS 2006
Session • objects for storing state in the data service resource across multiple requests. session attributes life-time:creating accessing terminating explicit session implicit session VO Tutorial @ CAS 2006
Perform document • the documents used by clients to describe the activities that they wish a data service resource to execute VO Tutorial @ CAS 2006
Response document • the documents that describe to clients the results of the processing of perform documents by data service resources. VO Tutorial @ CAS 2006
DAI’s Application China-VO DAS VO Tutorial @ CAS 2006
Aspects from OGSA-DAI as support for VO DAS • The basic operation to user registration database :delete、insert 、update etc. • ADQL query: synchronous and asynchronous • Get information: state and data URL • The basic operation to database in data node • Data can be transformed VOTable 、FITS 、ASCII VO Tutorial @ CAS 2006
Extended characteristics OGSA-DQP (Distributed Query Processing ) It is an example of a data integration component • supports queries over OGSA-DAI data services and over other services available on the Grid, thereby combining data access with analysis; • adapts techniques from parallel databases to provide implicit parallelism for complex data-intensive requests; and VO Tutorial @ CAS 2006
DQP framework consists of : • Grid Distributed Query Service (Coordinator) It is the main interaction point for the clients • Query Evaluation Service(Evaluator) It is used by the coordinator to execute query plans generated by the query compiler, optimiser and scheduler. VO Tutorial @ CAS 2006
More information is provided in the following address OGSA-DAI: http://www.ogsadai.org.uk/ China VO: http://www.china-vo.org VO Tutorial @ CAS 2006
Thank you! VO Tutorial @ CAS 2006